Ballistics by the inch

100k

So, a small milestone: sometime today this blog will break the 100,000 visits mark.

Not huge by the measure of many websites. But pretty respectable for a little blog where there isn’t a lot of posting. And it got to the 100k mark in less time, and with only about one-tenth of the posts, as my personal blog.

So, yay! Thanks to everyone who has stopped by or who has shared this blog with others. We appreciate your support!

 

Jim Downey

PS: Since I know someone will wonder, the BBTI site itself gets about 25,000 visits in a typical month, though that number can spike to 10x that size in months when we post new data. To date we’ve had something in excess of 25 million visits.

September 17, 2014 Posted by | Anecdotes, Links | , , | 4 Comments

And now for some newer guns.

Last week I posted about some historical reproductions. Now let’s have a quick overview of some newer guns we got to try on the same trip to the range. I’ll include some *very* brief comments, and may return to do longer reviews later when I have some additional time.

First up, the USFA ZiP .22LR, shown with 25-round mag for additional grip purchase:
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Comments: Ugh. I hated this gun. Seriously. It’s awkward to hold, worse to shoot, all sharp angles and weirdly thick. It’s the kind of ugly that isn’t even interesting. The design requires you to put your hand right up close to the muzzle to cycle the action. Since it was brand new, I’ll forgive it having problems cycling properly (this is fairly common with rim-fire guns which are brand new), but I sure as hell wouldn’t want to have to shoot it enough to break it in.

Bottom line: if someone insisted on giving me one of these, I’d just turn around and sell it to use the money for almost any other purpose.

 

Next, the Excel Arms MP-22 .22mag Accelerator:

 

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Comments: Nice gun. Shot very well, and the 8.5″ barrel is sufficiently long to get some benefit out of the .22WMR cartridge.  The heavy bull barrel also does a good job of taming the recoil and muzzle-flip, as can be seen in this vid:

 

Next, the SIG 232 .380acp:

 

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Comments: SIG SAUER’s version of the classic PPK. Just what you’d expect: quality, accurate, easy to shoot for even someone with large hands, as can be seen in this image of my buddy who has even larger hands than I do:

 

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Next, the Glock 42 .380acp:

 

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Comments: I did not expect to like this gun. I was REALLY surprised when I did. Seriously, it is the best-shooting Glock I’ve ever handled. For such a small gun, it fit my large hands comfortably and was easy to shoot well. With Glock quality and reliability, this may be the first .380acp I would seriously consider as a CCW gun.

 

Next, the Kimber Solo Carry 9mm:

 

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And here’s a vid of shooting it:

 

Comments: Kimber quality. Lot of power in a small package, and I felt it in the web between thumb and forefinger of my dominant hand. But that was just a sting, not uncomfortable, even shooting premium SD ammo. Another good candidate for CCW.

 

And here’s a quick look at an old classic: Winchester Model 70 XTR Featherweight in 6.5 Swedish (6.5mm x 55mm)

 

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Comments: Like I said, a classic. And as such, a known quantity. But the first time I’ve shot one in 6.5 Swede, and I was pleasantly surprised by how little recoil there was.

Well, that’s all that I have images of, though we also shot a Chiappa M1-22 and a KelTec PMR-30 .22 mag. Again, both are known quantities and shot as expected. Oh, and my buddy gave my Steyr S9 a go, and you can see that vid here.

As noted, I may revisit any of these with a longer review sometime later, but don’t hold your breath.

 

Jim Downey

 

August 26, 2014 Posted by | .22, .22WMR, .380 ACP, 6.5 Swedish, 9mm Luger (9x19), Anecdotes, Discussion. | , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Some black powder fun.

This past weekend I had the chance to do some black powder shooting with a couple of friends. Here’s most of the firearms we shot:

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From left to right: 15th century Handgonne (.75 cal), 16th century Japanese-style matchlock (.50 cal … I think), then a matched pair of smoothbore flintlocks from about 1760 (.69 cal). We also shot my 1815 Mortimer flintlock and a 1876 Hawken percussion cap rifle (.50 cal).

It was all kinds of fun. Here’s a short video of shooting the Handgonne:

 

Here’s a nice detail of the mechanism showing the match and pan on the matchlock:

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This clip of shooting it shows the problems inherent in having a match (the burning cord) which was actually too small:

 

Then here’s a shot of loading the Hawken:

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Examining it before shooting:

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And then shooting:

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And here’s a bit of video:

 

Some modern guns and short reviews of them to follow later this week.

 

Jim Downey

 

 

August 19, 2014 Posted by | Anecdotes | , , , , , , , | 1 Comment

Perceived recoil and bullet weight.

Got a great question recently, and I thought I would share some of my thoughts about it, then invite others to weigh in. Here’s the question:

I hope that you folks can help me with a question I have had for many years now. Why is the recoil so much heavier with lighter bullets in the same caliber and powder loadings than heavier bullets of the same caliber and loadings?

For example. With my S&W model 60, Gold Dot L/E 38 special 135 grain JHP +P loads recoil much harder than the Remington 125 grain JHP +P loads. The same thing happens with my Glock mod 23 .40cal when I shoot 180 grain JHP rounds vs 165 grain JHP rounds. The 165 grain rounds recoil much harder. One would think the heavier round with the same powder load would recoil harder. Can you help?

Perceived recoil is a surprisingly complex problem. It’s not just a matter of total force, but the ‘shape’ of the recoil impulse as well. Then there are the ergonomics of how a particular gun fits a particular person/hand. Add in the mechanical action of how the gun operates (some use part of the recoil energy to cycle the action, some don’t), and various psychological/physiological factors (are you tired? just had an adrenaline dump? afraid of a given gun/caliber/cartridge?), and you can see how many different factors might come into play.

A good place to start is to look at the equation for Muzzle Energy (ME). Let’s use the numbers for the Steyr M40 (very similar to your Glock 23) which was one of the ‘real world’ guns used in the .40 S&W tests we did. Calculations are from Airhog.

The 165gr Federal Hydra-Shok JHP has a velocity of 943fps out of the 4″ barrel. That gives a Muzzle Energy of 325.88ft-lbs.
The 180gr Federal Hydra-Shok JHP has a velocity of 989fps out of the 4″ barrel. That gives a Muzzle Energy of 391.04ft-lbs.

OK, that would seem to indicate that the heavier bullet should cause more recoil. The ME is higher, and you’re shooting them out of the same gun.

But I’m a little wary of that example. Usually, a lighter bullet is faster than a heavier one if they have the similar powder charge, out of barrels of the same length. Here’s another example, looking at 9mm from a Beretta 92.

The Cor-Bon 90gr JHP +P has a velocity of 1522 out of the 4.875″ barrel. That gives a Muzzle Energy of 463.05ft-lbs.
The Cor-Bon 125gr JHP +P has a velocity of 1291 out of the 4.875″ barrel. That gives a Muzzle Energy of 462.72ft-lbs.

And those are very close to the same amount of ME, and should feel about the same in terms of recoil were that the only factor.

So what’s going on? Why do we see one instance where the ammo is just a bit faster in the heavier bullet (resulting in higher ME), but much slower in another instance?

I suspect that it’s probably due to differences in loadings between the different ammo. Even with ammo from the same manufacturer (in the examples above), there’s nothing saying that they are using either the same propellant OR similar amounts of the same propellant for loadings which use different bullet weights. That means that trying to generalize the amount of recoil between different bullet weights just on the basis of brand is difficult if not impossible.

Furthermore, if you’ve done any reloading, or spend some time looking over reloading data, you’ll know that even when you’re using the same propellant in the same cases, different bullet weights usually means different bullets (in terms of manufacturer and/or shape) resulting in different seating depths and overall length. It may seem to be a trivial matter, but this results in different pressure profiles (the amount of pressure within the firing chamber of the gun). Just one example, taken from the Hodgdon Reloading site, for maximum-pressure loads using  GDHPs:

The 90gr bullet with 7.0gr of Longshot powder has an overall length of 1.010″ and gives a velocity of 1,378fps, a pressure of 32,300 PSI, and would have a ME of 379.57ft-lbs.
The 115gr bullet with 6.0gr of Longshot powder has an overall length of
1.125″ and gives a velocity of 1,203fps, a pressure of 32,300 PSI and would have a ME of 369.64ft-lbs.

Note that while the heavier bullet uses a full 1.0gr less of propellant and has a longer overall length, it generates the same amount of pressure. If we drop back to the same amount of the same powder for each loading (6.0gr), then the pressure generated in the lighter bullet loading drops to 29,400 PSI, velocity drops to 1,278fps, and ME drops to 326.48ft-lbs.

But not all pressure is created equal, even if it is nominally ‘the same’. The pressure impulse also matters. That’s the curve of how the pressure rises and falls over time, which is largely related to how ‘fast’ or ‘slow’ the propellant burns. Propellants used for handgun loads tend to be very ‘fast’ (burn rapidly), so the impulse tends to be sharper.  Here’s a good explanation of the matter.

And if you think about it, the heavier the bullet used, the longer/slower it takes to start moving when the cartridge is fired. That should mean that the impulse is spread out over a slightly longer time than it would be with a lighter bullet. So in some sense, the lighter bullet would result with a ‘snappier’ feel. And that may well be what it is that you’re feeling when you experience more perceived recoil (and have controlled for all the other factors) from lighter bullets.

Other thoughts on the subject?

 

Jim Downey

 

 

 

 

June 15, 2014 Posted by | .38 Special, .40 S&W, 9mm Luger (9x19), Data, Discussion., Links | , , , , , , , , , , , , , , , | Leave a comment

Questions, we get questions …

I thought I would share a question I got in email today, and my generalized answer, since it is something which comes up surprisingly often.

 

I love this data! Would it be possible to fund the testing of additional cartridges?  I’m looking for more .XYZ load tests.

Our baseline costs for testing a particular cartridge (out to 18″ barrel length) runs a couple hundred dollars for the barrel blank, then perhaps another hundred to get the smithing work done on it to fit the T/C platform. Then add in the actual cost of ammo, with a minimum of probably 100 rounds (3 shots at each inch of barrel, additional rounds for each ‘real world gun’, and then another box or two for repeats when something goes buggy with the data). So realistically, to actually fund a test sequence is a minimum of close to $500 for just one ammo load, and another $100+ for each additional ammo. Add in equipment and site hosting costs, and that’s how we’ve managed to spend something on the order of $50k so far for the data on the site. Which doesn’t include any labor costs, of course, since we only do this because we were curious about the data, not as any kind of testing business.

Which is to say that we’re always happy to accept donations and feedback on what sorts of things people would like to see, but as of yet no one has been willing to step up and finance an entire test sequence for something we’re curious enough to want to sink the time into. (Each test sequence takes 100 man-hours of labor or more … from our vacation/weekend/fun time.)

We don’t *currently* have any plans to retest the .XYZ anytime soon. Actually, we don’t have plans to do any specific tests at all in the near term. But we are looking at revisiting most or all of the cartridges tested to date at some point in the future, just to see how ammo quality/selection may have changed over a 5 or 10 year period.

 

Jim Downey

June 5, 2014 Posted by | Anecdotes, Data, Discussion., General Procedures | , , , , , , , , , | Leave a comment

Confirmation of the .460 Rowland performance.

John Ervin at Brass Fetcher Ballistic Testing has just put up a new page about his testing of the .460 Rowland cartridge. As I have explained in the past,  our work at BBTI is intended to be an overview of how ballistic performance varies over barrel length — it is just a quick survey to get an idea of the general trends, not meant to be an in-depth examination of a specific cartridge.

But in-depth testing is exactly what Ervin does, using a larger sample size, ballistic gelatin, and high-speed videography. And as a result, his much more detailed analysis is more useful for getting into the details of a given cartridge out of a specific barrel length. And it is really good to see that his results confirm what I have been saying all along: that if you carry a .45, you should instead be carrying a .460 Rowland.

What specifics? Take a look at the performance of Speer 230gr Gold Dot HP .45ACP in terms of foot-pounds of kinetic energy transfer into 20% ballistic gel:

 

Pretty good, eh? It’s what we expect from the .45ACP: a solid energy dump and reasonable penetration.

Now let’s take a look at the same chart, but with the Speer 230gr Gold Dot HP in .460Rowland:

The curves don’t look that different on first glance, but pay close attention to the scale there on the left axis of each one: where the .45ACP tops out at about 72 ft/lbs about 2″ into the gel, the .460Rowland tops out at about 335 ft/lbs just before 2″. That’s more than 4x the energy transfer.

In fact, at 5″ of penetration, the .460Rowland is still dumping about as much energy as the .45ACP does at the maximum.

But there’s more than simple energy transfer involved in terminal ballistic performance. There’s also how well the bullet is designed, and whether it expands properly. This can be a big concern in “over-driving” a bullet, so that it breaks apart. Well, Ervin’s data also covers these comparisons quite well. For the two specific rounds cited above, the .45ACP expanded to 0.344 square inches of frontal surface, and was still 229.5gr of weight. And the .460Rowland expanded to 0.526 square inches of frontal surface, and was still 221.3gr of weight.

There’s a *LOT* more information at Brass Fetcher Ballistic Testing. Ervin has an extensive 17 page Ammunition Performance Data report in .pdf format which contains a ton of images, video, and data — more than enough to keep even a data-junkie like me busy for a long time. I urge you to take a good look at it, and to consider the thoughts which Ervin shares about this cartridge. But I will leave you with his opening sentence which sums it up very nicely:

The 460 Rowland represents the pinnacle of handgun calibers for self-defense.

 

Agreed.

Jim Downey

May 1, 2014 Posted by | .45 ACP, .460 Rowland, Data, Discussion., Links | , , , , , , , , , , , , , , , , , | Leave a comment

.460 Rowland case wall thickness.

A friend dropped me a note, after looking over my previous experiments with putting .460 Rowland load power into .45 ACP cases, and asked a fairly simple question: Do you think that the case walls are actually thicker in the .460 Rowland?

Now, I have read several articles over the years which mentioned that the .460 Rowland cases were “stronger” with others saying that the cases were “thicker”. In fact, in the blog post cited above, I myself said:

Even shooting them in a gun designed to handle .460 Rowland power was risky, since the .45 ACP cases do not have the same strength as the .460 Rowland cases.

But is that actually true?

Good question. My Lyman 49th Edition Reloading Handbook doesn’t give case wall thickness for the .45ACP, and doesn’t list .460 Rowland at all. A quick check online also didn’t turn up any case wall thickness specs for either cartridge. As noted above, there are some gun writers out there who claim that the .460 Rowland case has thicker walls “for strength” but this claim isn’t made on the 460Rowland.com site that I could find.

So, being the data-curious guy that I am, I decided to just take some measurements and see what I found.

The only .460 cases I have are all Starline brass (I ordered 500 from them, and supplemented with other brass from factory Buffalo Bore ammunition – again, all of it marked as Starline), and I went through and checked a bunch with my simple calipers. Now, those calipers aren’t the pincer type, just the standard parallel-jaws type, so I only trust the measurements to about halfway down the case. And they all fell into a range of wall thickness from 0.0012″ to 0.0014″.

Doing the same measurement with ten different ‘marked’ sets of .45 ACP brass I also have readily to hand, the results were almost identical, with the vast majority of cases being 0.0012″ or a thousandth of an inch on either side of that. It didn’t matter whether the cases were nickle-plated or marked “+P”. The ‘marked’ brass was as follows:

  • Cor Bon +P
  • ELD
  • Federal Brass
  • Federal Nickle
  • R-P
  • S&B
  • Speer Brass
  • Speer Nickle
  • Starline
  • Winchester

And when you stop to think about it, there would be no reason or way for the case walls to be significantly thicker in the .460 Rowland cartridge, and still allow you to use standard .45 ACP reloading components and dies. If the case walls were substantially thicker, then you’d have to have slightly smaller bullets, if nothing else, and would probably need a different resizing die and/or neck expanding die.

Also, when I was conducting those experiments last summer, I didn’t note any differences in how the .45 ACP cases looked or functioned (when being reloaded) after being shot with .460 Rowland power loads.

My conclusion? That the .460 Rowland cases are no thicker walled than .45 ACP cases. They may still be “stronger”, if there is some metallurgical difference, but I doubt it. The real difference is in whether or not the chamber of the gun in which the ammo is being used is strong enough to handle the much-greater pressure of the .460 Rowland loads. Because remember, the maximum pressure for standard .45 ACP is just 21,000 PSI, and 23,000 PSI for .45 ACP +P — while the .460 Rowland cartridge reaches pressures of 40,000 PSI.

Of course, there are additional factors to consider (like recoil and timing) with the .460 Rowland cartridge, so you can’t just make the chamber of the gun stronger and then start putting those kinds of loads into .45 ACP cases. And you really wouldn’t want to accidentally put such power into a ‘normal’ .45 ACP gun — that could lead to catastrophic failure of the gun, and result in serious injury or death. So it still makes ALL KINDS OF SENSE to only load the longer .460 Rowland cases with that much power.

 

Jim Downey

March 22, 2014 Posted by | .45 ACP, .460 Rowland, Anecdotes, Data, Discussion. | , , , , , , , , , , , | 2 Comments

Help out those honoring veterans.

One of the traditions in the United States is that Military Funeral Honors for veterans can include a military rifle salute. This is usually provided by a local VFW or AL Post who are using specially adapted M1 Garand rifles loaned to them from the US Army.

The M1 was a fine rifle. But even the best machine suffers with age and use, and there have been instances where malfunctions have disrupted a rifle salute during funeral services.

The other day I got a note from John Ervin at Brass Fetcher Ballistic Testing about his efforts to help deal with these malfunctions. With his permission, here is an excerpt from his note:

When I worked for the US Army, I had the opportunity to be the Technical Lead of the ‘M1 Garand Malfunction-In-Field’ program.  This program addressed reliability and safety issues encountered by the Veterans as they shot the M1 Garand rifles in the three-volley salute during funeral ceremonies for fallen military servicemembers and past veterans.

An excellent rifle when firing ball ammunition, the M1 Garand rifles that are loaned to the VFW and AL Posts from the US Army can be well past their service life and are fitted with a Blank Firing Adaptor to exclusively fire blank ammunition.  During the two years that I was the Technical Lead on the program, I visited 10 Posts across the US and handled phone calls from Posts around the country reporting reliability problems, and occasionally – mechanical failures of the guns themselves.

* * *

Since the M1 Garand is no longer an issued weapon, funding to support its maintenance is limited.  But in the two years that I was on the program, I was able to plan and execute a (chamber and BFA) pressure test and slow-motion video shoot where we determined the root cause of the malfunctions and the cause of the M1 Garand receiver breakages.

 

There is a technical report available which resulted from John’s testing, but access is limited. This has presented something of a problem for some VFW and AL Posts in getting proper maintenance for their Garands used in the funeral honors.

And here is where you can help. Again, from John:

If you know of any VFW or AL Post who are experiencing malfunctions or breakages of the M1 Garand when firing M1909 Blank ammunition, please have them contact me.  I am happy to provide them technical support on their issue, free of charge.

 

That’s it. No donations asked. No need to write letters or make phone calls to government officials. Nothing like that. If you know of any VFW or AL Post which has had problems, just have them contact John, and he’ll help them get the problems resolved. That’s it. Just spread the word.

Thanks.

 

Jim Downey

March 20, 2014 Posted by | .30 carbine, Discussion., Links | , , , , , , , | Leave a comment

Stereotomy*

Cross posted  from my personal blog.

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For those who don’t know, one of my other interests is handgun ballistics research. Specifically, in regards to how barrel length effects bullet velocity for different cartridges and loadings. Even if you don’t like guns, the physics behind ballistic performance can be very interesting.

And here’s a wonderfully graphic image showing those physical forces:

Ruger Alaskan .44 Magnum

Text from the source to go with this image (site is Finnish, and English is not the author’s first language):

Let’s talk a bit about .44 Magnum cartridge. Despite of being very close to diameter of .45ACP the .44Mag is totally different beast. Average .45ACP round generates ~650J of hit energy while .44Mag makes easily 1600J and can be pushed much more beyond that. This specific gun however cannot utilize all potential of .44 Magnum cartridge because of very short barrel. It simply cannot burn all powder. As you can see there is huge cone shaped spray of unburnt stuff flying in the air. With longer barrel show would be different.

Ok, you may have noticed the flames. They are something we haven’t seen before. Especially when you look picture below and huge left side flame in it. Interesting thing is that major amount of the flame is escaping between cylinder and barrel. That short barrel seems to puff bullet our so fast that powder mass just flies out unignited.

The site is filled with a bunch of great high-speed camera images of guns being fired. And it also has something else which is new to me: ‘natural stereoscopic’ images of guns being fired. Like this one:

Now, what do I mean ‘natural stereoscopic’ images? Well, this is pretty cool itself. Here’s a reference link & explanation from the Kuulapaa site:

Help: How to Free-View the Stereo Pairs

Each stereo view consists of two images, one for each eye. Free viewing is the technique that will allow you to direct each of these images separately and simultaneously into each eye. Once that happens, you are said to have “fused” the pair of images into a stereo view.

At the bottom of this page a stereo pair of images is loading with which you can practice. All the stereo pairs shown on this site are in the “cross-eyed” format (my apologies to all the “wall-eyed” people). That means that the first (leftmost) image is for your right eye and the right image is for your left eye.

There are then a series of practice image to show what he means and give you a chance to develop this viewing skill. It works fairly well for me, but does tire my eye muscles fairly quickly. Give it a try and see how you do.

Jim Downey

*Couldn’t resist. Lyrics here.

 

February 1, 2014 Posted by | .44 Magnum, Discussion., Links | , , , , , , , , , , , , , , , , | 1 Comment

Rimfire Roundtable

Well, it’s too damned cold in most of the country to go out to the range, so if you’d like to see hear why I didn’t stay in radio as a career, and maybe enjoy some good discussion about rimfire cartridges and guns, take a listen to this new podcast:

Episode #26 Rimfire Roundtable #1

On this show I was lucky enough to round up three guys uniquely qualified for the first ever Rimfire Roundtable. We discuss what we would like to see come from the firearms industry regarding rimfire, better supplies of ammunition aside. I hope you enjoy our discussion and let us know your ideas too.

It’s about an hour long, all told, and in spite of my participation fairly interesting/informative. Check it out if you have some listening time!

 

Jim Downey

January 7, 2014 Posted by | .22, .22WMR, Anecdotes, Discussion., Links | , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Wait … it’s 2014?? How did THAT happen?

2013 was a busy year for BBTI.

We did the .22Mag tests. We did the 9mm Glock Tests. I got my .460 Rowland conversion up and running. And I found some really fun .44Mag +P+ loads, then figured out a simple hack so that they would feed reliably in my lever gun. Like I said, a busy year.

And we couldn’t have done it without help. Of several types. To see the list of those donors who have helped offset some of our operating costs, pop over to the BBTI site. And here’s a list of the top-10 referring sites (excluding search engines and Wikipedia):

  1. thefiringline.com
  2. defensivecarry.com
  3. guns.com
  4. thefirearmblog.com
  5. ar15.com
  6. thetruthaboutguns.com
  7. survivalistboards.com
  8. glocktalk.com
  9. reddit.com
  10. rimfirecentral.com

Altogether, we had 243,230 visitors to the BBTI website, and some 12,000+ views of this blog. Since we’ve gone through several iterations of the site over the last five years, it’s hard to say exactly how many visitors or pageviews or hits we’ve had in total — but it’s more than we ever really expected. Thanks, everyone.

And particular thanks to my Good Lady Wife, who has done all the webwork and most of the number crunching over the years.

We don’t currently have any concrete plans for new tests in 2014. But who knows? Keep an eye here and on our Facebook page for news.

Happy New Year, everyone!

 

Jim Downey

 

January 1, 2014 Posted by | 9mm Luger (9x19), .44 Magnum, Data, Discussion., Anecdotes, Links, .460 Rowland, .22WMR | , , , , , , , , , , , , , , , , , | 2 Comments

Some Muzzle Energy comparisons.

I got a nice note from Jason at Leaf Technologies, who had been curious about how different cartridges compared in terms of Muzzle Energy (ME). So what he did was take the data from BBTI and average the ME curves for the cartridges he was interested in, then plot them head-to-head in one Excel graph. He sent me the result, and with his permission I am sharing it here:

MEgraph

(Click to enlarge.)

I always love to see how others use our data, and the conclusions they draw from it. It’s EXACTLY the sort of thing we hoped would happen, and why we’ve made the data freely available. If you would like to read some of Jason’s conclusions, and the discussion they engender, pop over to the Northeast Shooters Forum.

And if you have your own interesting spin on how our data can be used in a new way, drop me a note. If I think it’d be of interest to others, I’ll be happy to post it here/link to it. Just send an email to jimd@ballisticsbytheinch.com

 

Jim Downey

December 12, 2013 Posted by | .357 Magnum, .357 SIG, .380 ACP, .40 S&W, .45 ACP, 10mm, 9mm Luger (9x19), Data, Discussion., Links | 1 Comment

Happy Thanksgivuk … er, I mean Birthday!

OK, first: Happy Thanksgiving to all my fellow Americans. And Happy Hanukkah to all who observe it!

But most of all,

Happy Birthday to BBTI!

Yeah, it’s our fifth birthday. We officially launched the site on Thanksgiving in 2008.  And it’s been a fun romp since then. We’ve gone through many different iterations on the site, adding in more calibers/cartridges, doing the big cylinder gap test, tweaking this and changing that. We’ve shot something on the order of 22,000 – 23,000 rounds. We’ve had something in excess of 20 million hits to the site. We’ve invested more than $50,000 and untold hundreds of hours of labor. And we’ve become pretty much the default resource for anyone who has needed (or just wondered about) data pertaining to handgun ammunition performance over barrel length. Like I said, it’s been fun! Thanks for helping to make it so!

And since it is our birthday, it’s time for a gift in the form of a whole new section to the BBTI website:

Polygonal v. Traditional L&G Rifling (“Glock tests”)

From that page:

For years people have wondered about the effects of the different styles of rifling, and whether one or the other would offer specific advantages for accuracy or velocity from a given cartridge.  But since many different factors can have an effect on both accuracy and velocity, these discussions have largely remained anecdotal.  We decided to see whether we could generate data as to performance differences between the two styles of rifling as concerns bullet velocity, using our standard chop-test techniques.  The data on this page is the result of those tests.

Check it out when you get a chance! And thanks again to all who have shared links to our site, who have sent us emails, who have contributed to help offset our costs — you folks have made our success possible, and it is very much appreciated.

 

Jim Downey

PS: as a personal thanks as well, I have made both my first novel and our care-giving memoir available for free download for today and tomorrow (Nov. 28th & 29th).

November 28, 2013 Posted by | 9mm Luger (9x19), Anecdotes, Data, Discussion., Links | , , , , , , , , , , , , , , , , , | 1 Comment

With charts! Graphs! Slo-mo!

John Ervin at Brass Fetcher Ballistic Testing has put together another great video presentation, showing in several ways how Jacketed Hollow Point (JHP) ammo performs in comparison to Full Metal Jacket (FMJ) ammo for 9 different handgun cartridges. It’s long (22 minutes), but very nicely documents just exactly how the two different bullet styles behave at handgun velocities. Here’s the video:

 

 

The cartridges covered are .22 LR, .25 ACP, .32 ACP, .380 ACP, 9mm Makarov (9×18), 9mm Police (Ultra), .38 Special, 9mm Luger (9×19), and .45 ACP.  His data and presentation makes a great companion to our own data, and I really recommend that you set aside the time to watch the video at your earliest convenience.

 

Jim Downey

October 22, 2013 Posted by | .22, .25 ACP, .32 ACP, .38 Special, .380 ACP, .45 ACP, 9mm Luger (9x19), 9mm Mak, 9mm Ultra, Data, Discussion., Links | , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Now, about those thunderbolts…

Some weeks back I put up a post about my preliminary experiences with a .460 Rowland conversion for my Glock 21 Gen 4. In it I mentioned how much I like the resultant gun, but also how I was having some problems with magazine wear when shooting full-force .460 loads.

Well, after thinking a lot more about it, as well as discussing it with people online and with the other BBTI members when they were here for the recent tests (one of whom has been a Glock armorer for 15+ years) a couple different strategies emerged for me to test. Briefly, those were:

  • See whether putting in a heavier mag spring would help
  • See whether the problem was due to the case length of the .460 Rowland cartridges (they’re 1/16″ longer than .45 ACP).
  • See whether the problem was due to the *power* of the cartridges rather than the length of the cases.

To test the first, it was a simple matter to get a more powerful mag spring and test it in one of the magazines. I picked up a Wolff magazine spring from Midway and did so.

To test whether it was the simple case length of the .460 Rowland cases, I made up some .460 Rowland rounds using .45 ACP reloading standards.

To test whether it was the *power* of the .460 loads but not the case length was another matter. Here’s where we get to the Don’t Try This At Home part of today’s blog post: I made up a number of .45 ACP rounds which were loaded to .460 Rowland specs.

Let me repeat that again: Don’t Try This At Home. These are wildcat rounds, and potentially dangerous. Shooting them in a gun not rated for .460 Rowland stresses could very well result in catastrophic failure of your gun, of the “KABOOM!” variety. Even shooting them in a gun designed to handle .460 Rowland power was risky, since the .45 ACP cases do not have the same strength as the .460 Rowland cases. I made up just 10 rounds of each of these loadings, and was careful to make sure I shot them all, so that they didn’t accidentally wind up in a .45 not strong enough to take the punishment.

Here are each of the loadings I made up, just for reference, along with their approximate chrono results:

  1. 185gr XTP bullet, .45 ACP case, .460 Rowland power  1480fps
  2. 200gr RNFP bullet, .45 ACP case, .460 Rowland power  1440fps
  3. 230gr RNFP bullet, .45 ACP case, .460 Rowland power  1350fps
  4. 250gr LFN bullet, .45 ACP case, .460 Rowland power  1250fps
  5. 230gr RNFP bullet, .45 ACP case, .45 ACP power  920fps
  6. 230gr RNFP bullet, .460 Rowland case,  .45 ACP power  925fps
  7. 185gr XTP bullet, .460 Rowland case, .460 Rowland power  1490fps
  8. 200gr RNFP bullet, .460 Rowland case, .460 Rowland power  1420fps
  9. 230gr RNFP bullet, .460 Rowland case, .460 Rowland power  1355fps
  10. 250gr LFN bullet, .460 Rowland case, .460 Rowland power  1265fps

No, I’m not going to give the specific powder amounts for any of those. I used Hodgdon Longshot powder, and you can look up the specs if you want to know more.

In addition, I had these factory loads on hand for comparison, along with their approximate chrono results:

11.  185gr DPX .45 ACP +P  1110fps

12.  230gr GDHP .45 ACP 850fps

13.  230gr JHP .45 ACP +P1040fps

14.  230gr JHP .460 Rowland  1380fps

15. 255gr LFN .460 Rowland1260fps

.460 Rowland loads

.460 Rowland loads

OK, a couple of comments before I go further: those are “approximate” chrono readings because I wasn’t being anywhere near as careful as we are when we do formal BBTI testing. To wit: I was just using one chrono; I wasn’t worried about getting the exact same number of readings (so long as I got three or four, I wasn’t too worried about it); and I didn’t do anything to control for consistent lighting or suchlike. But they should all be in the right ballpark.

So, looking over all those, you will see what I see: that there was a remarkable consistency in power levels, whether you’re looking at my reloads or factory loads, and between those rounds which used either .45 ACP cases or .460 Rowland cases. That tells me that following the published data for .460 Rowland reloads, and making some intelligent decisions on how to adapt those to the .45 ACP cases for purposes of this experiment, was by and large successful. Meaning that I can use those loads to fairly evaluate what makes a difference on the basic problem I was investigating: what is causing the magazine damage and how to resolve it.

So, what conclusions did I draw from all this?

First, the more powerful magazine spring seemed to help with consistent loading. I will be swapping out all the Glock 21 mag springs I have. This makes intuitive sense, since the slide is moving faster when shooting the more powerful rounds.

That doing a little customizing on the magazines also seems to help a great deal. Here’s a pic showing an unaltered magazine and one I have taken a Dremel tool to:

Glock 21 magazines

Glock 21 magazines

Note that these are just the magazine ‘boxes’ — the guts (spring, follower, etc) have all been removed for clarity.

With the altered magazine and stronger spring, any problems I had with Failure To Feed was minimized.

And most important, it is the *power* of the round, not the case length, which seems to cause damage to the unaltered magazines. Shooting the .460 Rowland power loads in the .45 ACP cases demonstrated this.  Conversely, shooting the .45 ACP power loads in the .460 Rowland cases didn’t cause any magazine damage at all.

Two additional notes I want to add: the first is that I had pretty consistent problems with the heavy Lead Flat Nose rounds in all configurations. They kept getting jammed up in transitioning from the magazine into the chamber. I’ll probably continue to experiment with this in the future, but I’m not too worried about it, since many guns run into some ammo specific problems.

The second is that once again I was really impressed at just how well this reconfigured Glock 21 did with .45 ACP loads. Seriously, with the .460 Rowland conversion in place, there was very minimal recoil (more than a .22, but not much) and it was VERY easy to control and shoot the gun well. I suspect that going forward the vast majority of the shooting I will do with this will be using standard .45 ACP reloads, saving the much more powerful .460 Rowland rounds for occasional practice. In this sense, I am thinking of the .45/.460 relationship the way I think about .38/.357 — it seems to be a perfectly appropriate analogy.

Now that I have all this sorted, I can go ahead and write up a formal review. But I thought I would share a little of the process of how I got to this point.

 

Jim Downey

October 15, 2013 Posted by | .357 Magnum, .38 Special, .45 ACP, .460 Rowland, Anecdotes, Data, Discussion., General Procedures | 15 Comments

How long is too long?

We’ve long known that many pistol calibers/cartridges are optimized for fairly short barrels — you see real benefits in increasing barrel length out to 6″ or 8″ or so, with diminishing returns beyond that. (The exception to this is the ‘magnum’ rounds: .44mag, .357mag, etc.) It’s not that you don’t see any benefit in a longer barrel, but the gain tends to flatten out. Take a look at the muzzle energy graph for the 9mm Luger (9×19) and this is quickly apparent:

Take a look at the left side of that graph. There’s some indication that the bullets are actually slowing down in the last couple of inches of an 18″ barrel. Whether or not this is just a glitch in our earlier test data, or an indication that friction is starting to win out over the remaining energy from the expanding gas of a fired cartridge is something I’ve always wondered about. Clearly, at some point a bullet will start to slow down, even stop; anyone who has ever fired a squib load and had to hammer the bullet out of a barrel knows that this can indeed happen. But at what point would this effect start to be clear?

Good question. And not one we really wanted to spend the money on to find out. See, the barrel blanks we’ve used all along came in an 18″ length standard for pistol calibers/cartridges. Longer barrels were available from different sources, but there was a big jump up in price for those, and it just didn’t make much sense to get into that.

However …

When we started to set up to do the so-called “Glock Tests” we had to find a different source for our barrel blanks, since our other supplier couldn’t provide a polygonal barrel (the kind of barrel Glock uses, though they are not unique in this). We sourced the barrels from Lothar Walther. And as it turned out, their barrel blanks are longer than 18″. Specifically, we received a 26″ barrel with traditional land-and-groove rifling and a 24″ barrel with polygonal rifling. Here they are:

9mm barrel blanks

9mm barrel blanks

So …

Well, we didn’t want to spend the time and money doing full chop tests from 26/24 inches down to 18″. But we did decide to just go ahead and get some benchmark data at the full length, just for shits and grins. And here is the data for those lengths, along with data from 18″, 17″, and 16″ lengths for comparison:

PNW Arms STD P 115gr SCHP

Trad:    1074 fps     1161 fps     1163 fps     1171 fps
Poly:    1064 fps     1131 fps     1131 fps     1135 fps

Federal STD P 115gr Hi-Shok

Trad:     1305 fps     1330 fps     1333 fps     1330 fps
Poly:     1323 fps     1331 fps     1336 fps     1135 fps

CorBon +P 115gr DPX

Trad:     1117 fps     1232 fps     1249 fps     1236 fps
Poly:     1057 fps     1186 fps     1195 fps     1208 fps

Black Hills +P 115gr JHP

Trad:     1494 fps     1508 fps     1512 fps     1498 fps
Poly:     1496 fps     1521 fps     1515 fps     1518 fps

Federal STD P 147gr JHP

Trad:     1036 fps     1061 fps     1084 fps     1085 fps
Poly:     1046 fps     1088 fps     1098 fps     1088 fps

So, there ya go: in each and every case, there is a noticeable decrease in velocity in going from an 18″ barrel to either the 24″ or 26″ barrel. And keep in mind that the protocols for this test were 10 shots of each ammo at each barrel length over two chrono units, rather than just 3 shots as we had done for previous chop tests.

Not too surprising, but nice to see actual data.

We hope to have the full data sets, with charts & graphs, up on the website soonish (maybe next week?). Watch here and on our FaceBook page for a posting when it is available.

 

Jim Downey

October 11, 2013 Posted by | 9mm Luger (9x19), Anecdotes, Data, Discussion., General Procedures | 5 Comments

M1 .30 carbine performance.

Got another nice email with a video link from John Ervin at Brass Fetcher Ballistic Testing, this time covering the performance of the venerable M1 Carbine .30 cal cartridge. From John:

Despite its handsome wood furniture and vaguely military-type appearance, the M1 Carbine is an effective firearm for self-defense and small game hunting.  Hornady makes ‘Critical Defense’ ammunition for it now and Federal continues to make its excellent 110gr SP, so good ammunition choices are available for M1 Carbine owners.

The M1 Carbine is excellent for its low recoil, small mechanical sight offset and cartridge that is sufficient in lethality to repulse human attackers (when using good soft point ammunition) at distance.

And here’s the video so you can see for yourself:

 

 

I’ll leave it at that for now … I have a lot to do this week to get ready for our 9mm “Glock Tests” this coming weekend. Yup, those are finally happening. I’ll post some preliminary thoughts/results probably this weekend or the first of next week, with full info to come after we have a chance to crunch the numbers a bit.

 

Jim Downey

October 1, 2013 Posted by | .30 carbine, 9mm Luger (9x19), Data, Discussion., Links | , , , , , , , , , , , , , | Leave a comment

It’s like flinging thunderbolts.

You may remember that I have a small bit of an obsession with the .460 Rowland cartridge.  Ever since we tested it for BBTI, I’ve wanted one. As I noted in one of those articles:

I said it before and I’ll repeat it here: if you carry a .45, you should instead be carrying a .460 Rowland.

 

So, early this year I put in an order for a .460 Rowland conversion kit for a new Gen 4 Glock 21.

I’m planning on doing a full formal review of the kit and the resultant gun, but I thought I’d share some of my experience so far. Why “so far”? Well, because I haven’t worked out all the minor kinks yet.

OK, first thing: it didn’t just take the 3 weeks for delivery which was promised. It wasn’t even 3 months. It was almost six months. And a buddy of mine who ordered his before I ordered mine still hasn’t gotten his. So, there’s that.

Second, and part of the reason for the delay, I didn’t receive a new barrel which was marked .460 Rowland. Rather, I got what looked like a standard Wolff .45 barrel. But it had indeed been rechambered to handle the .460 Rowland cartridge. Before I received the kit I got an email advising me of this problem, and I figured I could just roll with it. This is what I got in the kit:

.460 Rowland Conversion Kit.

.460 Rowland Conversion Kit.

 

Going clockwise from the top: That’s the threaded barrel, a screw-on compensator, spring assembly adapter, small serving of red loc-tite, and the heavy spring assembly (which is actually the Gen 3 design, but with the adapter works just fine in my Gen 4).

As advertised by .460 Rowland, the conversion takes like 30 seconds. If you can field strip your Glock, you can do the conversion. I’ve opted for using blue loc-tite rather than red, since it still works well but allows me to remove the compensator easily if I need to.

How does it work? Well, I’ve taken it out to the range several times now, shooting both factory rounds as well as my own reloads. Doing some informal chrono tests, I have gotten exactly the kind of performance promised and expected. The Buffalo Bore 230gr JHP were right at 1300 fps. 200gr RNFP reloads were at 1380 fps, and 185gr XTP (JHP) reloads were at 1410 fps. And those reloads are actually fairly mild — just 12.5gr of Longshot powder — based on what data I’ve seen, I could probably push that to 13.5gr without any risk. (Don’t consider this an endorsement — do your own research, and work up your own loads using published data and standard safety practices.)

Shooting the .460 loads out of the Glock is like shooting a .44 magnum (which I have a fair amount of practice with), but having 13 rounds on tap. Seriously, it’s like flinging thunderbolts with each shot. And the recoil is surprisingly manageable, though I’m not someone who is very recoil shy.

So, why did I say I was still working out the kinks?

Well, there’s a problem with the magazines. Here’s what happened after the first outing:

Glock 21 magazine

Glock 21 magazine

 

Look closely on the left side of that magazine, and you’ll see that there’s a tab which has been torn a bit loose and pushed forward. That’s from the force of the .460 cartridges slamming forward. At about this point the magazine would no longer release or insert smoothly. That was after my first outing, with about 60 .460 Rowland shots fired. And actually, I damaged two magazines to that extent with those 60 rounds.

So after that first outing, I took a Dremel tool to the magazines and cut away about 1/8″ of material, and flattened the whole face back into position. Today I took those two magazines back out to the range, and ran about another 50 rounds through the gun using the two of them. Here’s one of them after today’s outing, next to a new unaltered magazine:

Two Glock 21 magazines.

Two Glock 21 magazines.

 

More problems. This time, the little metal tab snapped off, as well as distorting the face of magazine again. Clearly, I need to sort out how to fix this.

Two other things I want to mention. One, I tried shooting standard .45ACP cartridges out of the .460 Rowland conversion. They work wonderfully. Seriously, there’s almost no recoil, the gun cycles just fine (with my mild reloads as well as factory +P self defense ammo), and there’s no accuracy loss that I could determine casually shooting the gun. So, that’s a plus.

But the other thing? Heh — take a look at what happened with my front site today:

Glock 21

Glock 21

Yeah, it really shouldn’t be facing that way, nor sticking up quite so much. But I can fix that easily enough.

If you have thoughts on how I can correct the magazine problem, I’d love to hear ‘em.

 

Jim Downey

September 23, 2013 Posted by | .45 ACP, .460 Rowland, Anecdotes, Discussion. | , , , , , , , , , , , , , , , , | 7 Comments

Buckshot effectiveness at 50 yard range.

John Ervin at Brass Fetcher Ballistic Testing is a friend, and I have a lot of respect for his research. We talked about this project a while back, figuring out how to get reliable data, and it’s cool to see the results.

The whole vid is worth watching, but if you’re looking for just the results, skip to about 7:00. For his conclusions based on the results (with some excellent advice), skip to about 9:30.

Bottom line: use at least 00 buckshot, if you want it to be effective out to 50 yards.  Know your gun, and test it to see what loads perform best at that distance.

 

Jim Downey

September 15, 2013 Posted by | Data, Discussion., Links, Shotgun ballistics | , , , , , , , , , , , , | 1 Comment

Just take a little off the sides, leave the top alone.

So, yesterday was our best day ever for this blog, doing 50% more traffic than any previous day. Why? Well, thanks to a link from The Firearm Blog about my experiments to alter the Buffalo Bore 340gr .44mag loads I’ve written about recently. So I wanted to say thanks to Steve over there, and to all his readers.

And I also wanted to report how the rounds behaved after a trip to the range this morning. I think pictures tell the story just fine. Here’s the first one:

20130829_105140

That’s a 3″ circle, just for reference. Those are three shots, fired from a sitting position at 50 yards (well, paces, so something pretty close to 50 yards). That’s with the standard, unaltered, 340gr rounds from my Winchester 94AE which has the standard iron sights. I wasn’t trying for super accuracy, just the sort of quick sight and shoot you’d do when hunting at that range. It may be worth noting that I had to hand-feed each round into the chamber of the gun, since these unaltered cartridges will not feed from the tube magazine. If you look close, you’ll see that I marked through each hole with a blue Sharpie.

Here’s the second picture:

20130829_105528

Exact same parameters as the first pic, but this time with three rounds which had been shaved as discussed in the previous posts. And since these rounds will reliably feed from the tube magazine, they were shot then the gun was cycled and then the next shot taken in fairly quick sequence. For clarity, I marked through the second set with a red Sharpie.

My conclusion? They’re as accurate as the unaltered cartridges. Which is to say, within the limits of my ability using them like that. With a good shooting rest and a scope you might be able to tell a difference, particularly at greater range. But for what I wanted them for, they’re entirely suitable. YMMV.

 

Jim Downey

August 29, 2013 Posted by | .44 Magnum, Data, Discussion., Anecdotes, Links | , , , , , , , , , , , , | Leave a comment

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