Ballistics by the inch

2016 in the rear-view mirror.

Happy New Year!

A quick recap of the last year: surprisingly active.

It’s interesting to see how things have evolved with BBTI over time. The last test sequence we did was the .45 Super /.450 SMC tests, with the data published in October 2015. So without new test results last year, we didn’t have the usual big spike in site visits. But we still saw a total of 447,203 visitors last year, which ain’t too shabby.

And last year we saw an evolution in who were our biggest referrers, as well. Excluding search engines, here they are in order:

  1. DefensiveCarry.com
  2. Guns.com
  3. MechTech Systems
  4. Wikipedia
  5. The Firearm Blog
  6. reddit
  7. Active Response Training
  8. Survivalist Boards
  9. The Firing Line
  10. AR15.com

All but four (Guns.com, MechTech Systems, Wikipedia, and The Firearm Blog) are discussion forums, and of those four The Firearm Blog also has a very active discussion community. MechTech Systems sells conversion kits for pistols, allowing you to turn your pistol into a carbine, so it makes perfect sense that they would link to us showing the advantage you can gain with a longer barrel.

In other words, most of the referrers are places where BBTI is being cited as a reference to help people make decisions about their firearm choices. That just makes sense, and corresponds to the email we get, thanking us for our site or asking for clarification/recommending new ammo to test. After 8 years, and with no new tests, there’s not much reason for the ‘news’ sites to mention us — but there’s still plenty of interest in the firearms community in the data we provide.

So thanks to all who share our site with others! You’re the real reason our site is a success!

 

Jim Downey

 

January 1, 2017 Posted by | .45 Super, .450 SMC, Data, Discussion., Links | , , , , , , , , , , , , , , , , , , , , , | Leave a comment

Effective shotgun ranges.

One of the questions we get regularly is asking whether we’re going to do some velocity/chop tests on shotguns. For a variety of reasons (both logistical & legal) we’ve decided that such tests are beyond the scope of what we want to tackle.

But that doesn’t mean that it’s not something of interest to us, collectively and individually. I’ve previously posted about tests which John Ervin at Brassfetcher has conducted showing the effectiveness of buckshot at 50 yards. And from personal experience, I knew that slugs from a 12 gauge are effective for hunting (or self defense) out to 100 yards, depending on the skill of the shooter.

But how about slugs at 200 yards? And how about DIY ‘cut shells’, which mimic slugs? And, say, if you did happen to hit a target at 100 yards with buckshot, would it be lethal?

Via The Firearm Blog, this video explores all these questions, and provides some VERY interesting answers:

It’s well worth the time to watch the whole thing. But the bottom line is that 00 Buckshot pellets would still be lethal at 100 yards, if you could connect with your target. And slugs? Easily to 200 yards, with a fair amount of control on hitting your target. At 300 yards, they’re still effective, but the trajectory is such that it’s much more difficult to reliably hit the target. And at 400 yards … well, watch to video to see for yourself.

Kudos to Iraqveteran8888 for conducting some really solid and informative tests, and sharing that information with the public.

 

Jim Downey

July 16, 2016 Posted by | Anecdotes, Data, Discussion., Links, Shotgun ballistics | , , , , , , , , , , , , , , , , , , , | Leave a comment

Dealing with power.

About 40 years ago, when I was an idiot teenager (yeah, I know — redundant, particularly in my case), we got this ’48 Willys Jeep. Since the engine was shot, we dropped an Olds V-6 in it. This was, essentially, like strapping a rocket to a skateboard. And it was too much power for idiot teenage me to handle.  Twice I snapped the driveshaft on the thing, just dumping the clutch too damned quickly. Twice. My uncle (who I lived with) was certain that I had been racing or something similar. The truth was, I didn’t even have that much of an excuse; I had simply goosed the engine too much and popped it into gear too fast. The original driveshaft just couldn’t handle that much of a power spike.

This is kinda what happens to your poor .45 ACP firearm when you decide to run some .45 Super through it.

With the Jeep, we wound up putting a more robust driveshaft in it. And I learned that if I wanted to keep driving it, I needed to be less of an idiot.

This analogy holds to how you should approach handling .45 Super power out of your .45 ACP gun. Chances are, very occasional use of these much more powerful loads won’t cause any problem in a quality, modern-made firearm. But if you’re smart, you’ll either greatly limit how many times you subject your gun (and your body) to that amount of power, or you will take steps to help manage it better and extend the life of your gun.

Typical ‘standard’ (non +P) .45 ACP loads tend to have a maximum pressure of between say 15,000 PSI and about 18,000 PSI. When you get past that, you get into ‘over-pressure’, or +P territory, up to about 23,000 PSI. This is the range most common modern firearms are built to handle safely.

But .45 Super generates more chamber pressure than that. How much more? Well, it’s a bit difficult to say, since there is a surprising dearth of data readily available. Neither my 49th Edition of Lyman’s Reloading Handbook nor my 13th Edition of Cartridges of the World have data for the .45 Super. Real Guns has some reloading formulas for .45 Super which give results consistent with our tests, but there are no pressure specs listed. Hodgdon Reloading has some pressure specs (in C.U.P.), but all their listed results for .45 Super are well below what our tests results were. Wikipedia lists .45 Super as having a maximum pressure of 28,000 PSI, and given that .460 Rowland is usually considered to run 35,000 – 40,000 PSI, that is probably in the correct ballpark.

I have written previously about converting a standard Glock 21 from .45 ACP over to .460 Rowland, and what is involved with that. Specifically, a new longer barrel with a fully-supported chamber which accommodates the longer case of the .460 Rowland, a 23 pound recoil spring, and a nice compensator to help tame the recoil. I also changed out the magazine springs, using an aftermarket product which increases the spring power by about 10%. This is because even with the other changes, the slide still moves much faster than with .45 ACP loads, and the increased mag spring power helps with reliability in feeding ammo. But even with all of that, shooting full-power .460 Rowland loads tends to cause damage to my magazines (as seen in the linked post).

Do you need to do all that in order for your firearm to handle frequent use of .45 Super loads? Well, I think that if you want to use a .460 Rowland conversion kit, it *will* tame the amount of recoil more than enough, but I don’t think that it is necessary to go quite that far. I should note that I have now run several hundred .45 Super loads through my Glock 21, and the gun has operated flawlessly — WITHOUT any damage to the magazines.

Converted G21 on left, G30S on right.

Converted G21 on left, G30S on right.

Rather, I think that the smart thing to do is to start off with going to a heavier recoil spring, perhaps swapping out a metal guide rod for a plastic one (if your gun comes with a plastic guide rod). Stronger magazine springs are probably still a good idea, to aid with reliable feeding. If suitable for your gun, add in a recoil buffer. These are the steps I have taken with my Glock 30S, and am planning for my Beretta Cx4 Storm. So far I have put a couple hundred .45 Super loads through the G30S with this configuration, and it has operated without a problem — again without any damage to the magazines.

As I said in my previous blog post, I still think that the .460 Rowland is a hell of a cartridge. But I think that the .45 Super offers almost as many advantages to the average shooter, with less hassle. I would still recommend that anyone who intends on shooting more than the very occasional .45 Super loads out of their gun consider making some simple changes to handle the additional power and extend the life of their gun. Don’t be like the idiot teenage me; deal with the power intelligently.

 

Jim Downey

 

 

November 1, 2015 Posted by | .45 ACP, .45 Super, .450 SMC, .460 Rowland, Data, Discussion., Links | , , , , , , , , , , , , , , , , , , , , , | 5 Comments

Saying farewell to an old friend.

I’ve decided to say farewell to an old friend who has rarely left the safe in the last couple of years.

So if you know anyone who might be interested in a very early (and collectible) Rohrbaugh R9, have ’em take a look at these images and then go on over to Gunbroker (I’ll link to the auction when it is live). I’m selling the gun with all the items shown.

Left

Rohrbaugh R9

Right

Internals

Internals

Frame interior

Frame interior

Underside

Underside

Holstered

In custom pocket holster

Holstered2

Holster has a detachable back to mask the shape of the gun

Kit

Original case & paperwork, replacement springs, take-down tool set are all included.

As I noted in my review of the R9 from three years back, it’s a fantastic little firearm, and incredibly well made. But as I also noted in that review, I had stopped carrying it much even then. I realized recently that I hadn’t taken it out to shoot for a couple of years. And that just ain’t right.

So I’m going to find it a new home. One where it will be appreciated.

Spread the word. Thanks.

Jim Downey

EDITED TO ADD: Sale concluded happily, and this nice little gun has found a new home. Thanks, everyone!

August 19, 2015 Posted by | 9mm Luger (9x19), Links | , , , , , | 5 Comments

That’s … unexpected.

Checking this morning’s stats (which I do pretty much every morning, over my first cup of coffee, just out of idle curiosity), I saw that there was an incoming link … from the Washington Post.

???

So I followed the link back, read the article, and didn’t see anything in it about BBTI. However, given the topic of the article (actually, it’s an editorial), I figured that I’d find the incoming link in the comments. And here it is:

enzo11

3/13/2015 3:58 PM CST [Edited]

There are actually many very short barreled pistols ( 7 inch, on down to Derringer-sized under-3 inch) available chambered for the .223 round.

But what this idiot of an author forgets is basic physics : the shorter the barrel, the lower the muzzle velocity. The lower the muzzle velocity, the less penetrating power the bullet has – by a large factor ( the energy is partially determined by the square of the velocity).

For a chart on muzzle velocity for different barrel lengths:

http://www.ballisticsbytheinch.com/223rifle.html

For what that does to the available energy:

http://www.ballisticsbytheinch.com/2011graphs+/223…

 

OK, BBTI wasn’t actually cited by the Washington Post. But it’s still amusing.

 

Jim Downey

March 15, 2015 Posted by | .223, Data, Discussion., Links | , , , , , , , , , | 1 Comment

No matter which way you look …

…whether back over 2014, or forward into 2015, things are pretty good vis-a-vis BBTI.

Yeah, 2014 was pretty good. We didn’t do any formal testing, though I did some informal testing and a fair number of reviews of new guns or guns which were just new to me.  Having the chance to do those now and again is enjoyable, without having the same deadline pressures I had when I was doing regular columns and reviews for Guns.com.

The numbers also look pretty good for 2014. This blog went from about 12,000 visits in 2013 to 22,000 last year – nearly double. And the BBTI site itself jumped from 243,230 visitors in 2013 to 318,304 visitors in 2014 — an increase of about a third. Visits have also continued to climb pretty steadily from day-to-day, with typically about 1,250 or so daily by the end of the year. Given that we didn’t do any new testing, that’s pretty impressive.

And of course, we’d like to thank all who linked to us over the past year. Here’s the top ten referring sites for 2014, excluding search engines and Wikipedia:

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

How about the year to come, then?

Well, we’re planning on doing one largish series of tests, to cover .45 Super, .450 SMC, and a number of additional .45 ACP loadings. We haven’t yet set a date for this sequence, but I will post a note about it here and on our Facebook page once plans solidify.

And behind the scenes, improvements continue at the BBTI website. We recently upgraded our hosting set-up, to shift over to more modern software technology. We’ve started discussing how we can do better presentations of our graphs and spreadsheets. I would still very much like to work with someone to develop a mobile app — if you have the necessary skill set to do that, please drop me a note. And whenever someone finds a glitch in our data or how the site renders for them, we try and make the corrections. None of this is very obvious, but it is all a lot of work, and I’d like to once again thank our web guru (and my lovely wife) at Coeurbois Graphic Design for her efforts.

Lastly, thanks to all who use the site regularly, who cite us in online discussions, who help to spread the word. And especially, I would like to thank all who have donated to BBTI in the last year — your tangible contributions make a difference, and help to offset our ongoing costs.

Happy New Year!

 

Jim Downey

January 2, 2015 Posted by | .45 ACP, .45 Super, .450 SMC, Boberg Arms, Data, Discussion., Links | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 1 Comment

Six shooter.

Well, well, well, BBTI made it to six years of shooting fun and research!

Yup, six years ago today we posted the first iteration of Ballistics By The Inch, and included data for 13 different handgun cartridges. Since then we’ve continued to expand on that original research, including some extensive testing on how much of an effect the cylinder gap on revolvers has, what performance differences you can expect from polygonal over traditional land & groove rifling, and added another 9 cartridges, as well as going back and including a very large selection of real world guns in all the different cartridges. This blog has had 100,000+ visitors and the BBTI site itself has had something like 25 – 30 million visits (the number is vague because of changes in hosting and record-keeping over time).

We’ve had an impact. I’ve seen incoming links from all around the world, in languages I didn’t even recognize. There’s probably not a single firearms discussion group/blog/site out there which hasn’t mentioned us at some point, and our data is regularly cited in discussions about the trade-offs you make in selecting one cartridge or barrel length over another. I’ve answered countless emails asking about specific points in our data, and have been warmly thanked in return for the work we’ve done. And on more than a few occasions people have pointed out corrections which need to be made, or offered suggestions on how we could improve the site, sometimes providing the results from their own crunching of our data.

When we started, it was fairly unusual to see much solid information on ammo boxes about how the ammunition performed in actual testing. Now that information is common, and expected. Manufacturer websites regularly specify real performance data along with what kind of gun was used for that testing. And the data provided has gotten a lot more … reliable, let’s say. We’ve been contacted by both ammo and firearms manufacturers, who have asked if they can link to our data to support their claims of performance — the answer is always “yes” so long as they make it clear that our data is public and not an endorsement of their product. And we’ve never taken a dime from any of those companies, so we can keep our data unbiased.

And we’re not done. We have specific plans in the works to test at least one more new cartridge (and possibly revisit an old favorite) in 2015. I try to regularly post to the blog additional informal research, as well as sharing some fun shooting and firearms trials/reviews. There’s already been one firearms-related patent issued to a member of the BBTI team, and we’ll likely see several more to come. Because we’re curious guys, and want to share our discoveries and ideas with the world.

So, onward and upward, as the saying goes. Thanks to all who have cited us, written about us, told their friends about us. Thanks to all who have taken the time to write with questions and suggestions. And thanks to all who have donated to help offset the ongoing costs of hosting and testing — it makes a difference, and is appreciated.

 

Jim Downey

November 28, 2014 Posted by | .22, .223, .22WMR, .25 ACP, .30 carbine, .32 ACP, .32 H&R, .327 Federal Magnum, .357 Magnum, .357 SIG, .38 Special, .380 ACP, .40 S&W, .41 Magnum, .44 Magnum, .44 Special, .45 ACP, .45 Colt, .460 Rowland, 10mm, 6.5 Swedish, 9mm Luger (9x19), 9mm Mak, 9mm Ultra, Anecdotes, Data, Discussion., General Procedures, Links, Shotgun ballistics | , , , , , , , , , , , , , , , , , , , , , | 1 Comment

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

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

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

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.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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 | .22WMR, .44 Magnum, .460 Rowland, 9mm Luger (9x19), Anecdotes, Data, Discussion., Links | , , , , , , , , , , , , , , , , , | 3 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 | 2 Comments

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

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

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 | , , , , , , , , , , , , | 2 Comments

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, Anecdotes, Data, Discussion., Links | , , , , , , , , , , , , | Leave a comment