Ballistics by the inch

What a difference just an eighth of an inch makes.

Recently I came across on a surprisingly good deal on a Taurus Tracker .44mag snubnose. This one:

Taurus isn’t my first choice of firearm brands, but I’ve owned them and generally liked them, and the price on this one was a little too good to pass up. So I got it, figuring that it would be an interesting addition to my collection, occasionally using it as a carry gun.

After shooting it with a variety of .44special and .44mag loads that I had on hand, I decided that what I wanted to use as a carry ammo was something we’d tested: Corbon’s 165gr JHP.  The lighter weight bullet would mean a lower felt recoil. And I knew how it would perform out of a short barrel, and estimated that I would get about 1150fps and just under 500ft/lbs of muzzle energy from the round. I checked locally, and the ammo wasn’t available, so I ordered in five boxes from a source online.

When it arrived, I did the logical thing and inserted five rounds into the Taurus, then closed the cylinder.

Er, make that I *tried* to close the cylinder. Because it wouldn’t. Huh?

I examined the gun. I had not noticed that the cartridges hadn’t gone completely into the chambers. The rims of the cartridges were all about 1/16th inch out.  Oops. That was a mistake on my part — I should have been paying closer attention when handling the new untested ammo, rather than just assuming that it would load properly. This is what it looked like after I removed one cartridge for contrast:

 

Even lightly tapping the cartridges wouldn’t get them to load properly (where the rim is down on the rear cylinder face). I removed the rest of the cartridges, examined the gun to make sure everything was otherwise functioning properly. It seemed to be. I looked over the cartridges, and they seemed to be fine, as well. So I got a couple of different .44 loads — a mix of .44sp and .44mag — and put them into the cylinder. They all loaded just fine, the cylinder closed, and there were no problems. Here are a Hornady and a Winchester .44mag round in the cylinder, with one of the Corbon; note the difference:

 

Hmm.

Next, I got my Colt Anaconda .44 out of the safe. I tried the same ammo in it, and this is what I found:

Exact same problem. So, presumably, it was the Corbon ammo. I removed the rounds from the gun.

And grabbed my digital calipers. I started checking all the dimensions on the Corbon ammo. In fact, I went through and checked several sample cartridges from all five boxes. As far as I could tell, everything was in spec. The cases were the exact correct length. And width, both at the mouth of the case, along the body, and just above the rim. The bullets were the correct diameter. And the over length of the cartridges was well within the normal range of .44magnum rounds.

WTH?

I set the conundrum aside, so my subconscious could chew it over for a few hours. The likely explanation hit me while taking a shower the next morning. Here, look at the images of the three different rounds mentioned above, and see if you can spot it:

Here’s a hint: the Corbon cartridge is in the center.

Got it?

Yeah, if you look very carefully, you’ll see that the SHAPE of the Corbon bullet is different than the others. Note how it almost swells a bit, going up from the mouth of the case, to about an eighth of an inch, before narrowing down. Whereas the Winchester (on the left) and the Hornady (on the right) both have a smooth ogive right from the mouth of the case until coming to a flat nose (actually, the Hornady, like the Corbon, is a hollow point, but you can’t see that from this image).

So why did this cause the problem?

The explanation requires a bit of detailed knowledge about how a revolver works. If you already know all this, my apologies. For those who may not …

Each chamber in a revolver has to be big enough to accommodate the case of the cartridge. But the bullet is slightly smaller than that, so that it fits inside the cartridge case.

Now, when a chamber on a revolver rotates into position aligned with the barrel, there’s always a chance that it might not be perfectly aligned. Just a few thousandths of an inch misalignment can lead to all kinds of bad things happening, from parts of the bullet being shaved off and spit out the sides of the ‘cylinder gap‘ to the gun going KABOOM in your hand. So revolver manufacturers have come up with two nifty ways to deal with this:

  1. Narrowing the chamber in front of the cartridge case slightly by tapering it.
  2. Having a ‘forcing cone‘ before the barrel that is just a little bit bigger than the bullet, to funnel it into the barrel.

So, the problem with the Corbon ammo was that shape of the bullet in the pic above. Note how it doesn’t smoothly curve in like the other two bullets. Rather, that slight swelling is probably hitting the taper inside the chambers, stopping the cartridge from seating properly.

And before you say that this is a problem with the Taurus being poorly made, note that I ran into the exact same problem with my Anaconda — widely considered a very good quality gun.

Now, the folks at Corbon are smart. I’m sure their engineers actually tested this ammo in some typical .44magnum revolvers. But all it would take is for slight differences (think a couple thousandths of an inch) in the rate or position of that chamber tapering from manufacturer to manufacturer to cause this problem. Chances are, they just didn’t test it in a Taurus .44 of this model, or a Colt Anaconda. It is also possible that this batch of bullets (all five boxes I got are from the same lot — I checked) is just slightly out of spec, but no one has yet noticed it in their guns, because the tolerances in other manufacturers are a little bit different.

Either way, I’m fairly sure that I could just take some sandpaper or a fine file to that slight swelling on the bullets, and they’d fit right into my gun. But first I’m going to wait and see whether I hear back from Corbon about this issue (yeah, I sent them an explanatory email a couple days ago).

Oh, one last thing: in the process of going through all of this, I noticed that the cylinder length (from the front face to the rear face of the cylinder) on the Taurus was 1.625″, or 1 5/8″, whereas the cylinder length on my Anaconda is 1.75″, or 1 3/4″ — an eighth of an inch difference. As I recall, 1.75″ is standard for .44magnum revolvers. Interesting that the Taurus is slightly shorter, and that may indeed have had something to do with the shape of the chambers on the gun.

Edited, 2/27: Just a quick note. I’ve had some friends check other brands of .44mag revolvers. Seems that Smith & Wesson makes theirs with a cylinder length of 1.6875″ (1 11/16th”), and Ruger 1.75″ (1 3/4″). So there’s more variation than I thought.

 

Jim Downey

February 26, 2020 Posted by | .44 Magnum, .44 Special, Anecdotes, Data, Discussion., Revolver | , , , , , , , , , , , , , , , , , , | Leave a comment

Reprise: Levering the Playing Field: a Magnum Opus

Prompted by my friends over at the Liberal Gun Club, this is another in an occasional series of revisiting some of my old articles which had been published elsewhere over the years, perhaps lightly edited or updated with my current thoughts on the topic discussed. This is an article I wrote for Guns.com, and it originally ran 3/26/2011. Some additional observations at the end.

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

In an earlier article, when I said you’d get about a 15% increase in bullet velocity when using a pistol caliber carbine over a handgun, I lied.

Or, rather, I was neglecting one particular class of pistol ammunition which can develop upwards of a 50% increase in velocity/power in a carbine over a handgun: the “magnums,” usually shot out of a lever-action gun. This would include .327 Federal Magnum, .357 Magnum, .41 Magnum, and .44 Magnum.

These cartridges are rimmed, initially developed as powerful handgun rounds, and have their origins in black powder cartridges. This history is important for understanding why they are different than most of the other pistol cartridges and the carbines that use them.

We’ll start with the .357 Magnum, the first of these cartridges developed.

Back in the 1930s a number of people, Elmer Keith most notable among them, were looking to improve the ballistic performance of the .38 Special cartridge. This had been a cartridge originally loaded with black powder. Black powder takes up a lot of space – typically two to four times as much space as smokeless powder of a similar power. Meaning that when people started loading .38 Special cartridges with smokeless powder, the cartridge was mostly empty.

Now, if you were looking to get more power out of a .38 Special, and you saw all that unused space in the cartridge, what would be the obvious thing to do? Right – add more smokeless powder.

The problem is, many of the handguns chambered for the .38 Special using black powder were not strong enough to handle .38 Special cartridges over-charged with smokeless powder. And having handguns blowing up is rough on the customers. Heavier-framed guns could handle the extra power, but how to distinguish between the different power levels and what cartridge was appropriate for which guns?

The solution was to come up with a cartridge, which was almost the same as the .38 Special, but would not chamber in the older guns because it was just a little bit longer. This was the .357 Magnum.

There are two important aspects of the cartridge as far as it applies to lever guns. One is just simply the ability to use more gunpowder (a typical gunpowder load for a .357 magnum uses about half again as much as used in a .38 Special.) And the other is that you can get more complete combustion of the gunpowder used, perhaps even use a much slower burning gunpowder. This means that the acceleration of the bullet continues for a longer period of time.

How much of a difference does this make? Well, from the BBTI data for the .357 Magnum, the Cor Bon 125gr JHP out of a 4″ barrel gives 1,496 fps – and 2,113 fps out of an 18″ barrel. Compare that to the .38 Special Cor Bon 125gr JHP out of a 4″ barrel at 996 fps and 1,190 fps out of an 18″ barrel. That’s a gain of 617 fps for the .357 Magnum and just 194 fps for the .38 Special. Put another way, you get over a 41% improvement with the Magnum and just 19% with the Special using the longer barrel.

Similar improvements can be seen with other loads in the .357 Magnum. And with the other magnum cartridges. And when you start getting any of these bullets up in the range of 1,500 – 2,000 fps, you’re hitting rifle cartridge velocity and power. The low end of rifle cartridge velocity and power, but nonetheless still very impressive.

There’s another advantage to these pistol caliber lever guns: flexibility. Let’s take that .357 again. On the high end of the power band, you can use it as a reliable deer-hunting gun without concern. But if you put some down-loaded .38 Special rounds in it, you can also use it to hunt rabbit or squirrel. I suppose you could even use snake/rat shot loads, though most folks don’t recommend those loads due to concerns over barrel damage. Shooting mild .38 Special loads makes for a great day just plinking at the range.

One thing that I consider a real shame: you can get good quality lever guns for the .357, the .41, and the .44 magnums. But to the best of my knowledge, no one yet makes a .327 Magnum lever gun. I would think that such a gun would meet with a lot of popularity – properly designed, it should be able to handle the .327 Federal Magnum cartridge, the .32 H&R cartridge, even the .32 S&W Long. Again, with the right powder loads, this would give the gun a great deal of flexibility for target shooting and hunting small to medium sized game/varmits.

So, if you like the idea of having a carbine in the same cartridge as your handgun, but want to be able to maximize the power available to you, think about a good lever gun. It was a good idea in the 19th century, and one that still makes a lot of sense today.

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

Some additional thoughts …

I’m still a little surprised that no manufacturer has come out with a production .327 mag lever gun, though occasionally you hear rumors that this company or that company is going to do so. But I must admit that as time has gone on I’ve grown less interested in the .327 cartridge, since firearms options are so limited — definitely a chicken & egg problem.

One very notable absence from the above discussion is the .22 WMR (.22 Magnum), for the simple reason that we hadn’t tested it yet when I wrote the article. You can find a later article about it here.

Something I didn’t address when I wrote the article initially was ammunition which was formulated to take greater advantage of the longer barrel of a lever gun. Several manufacturers produce such ammo, perhaps most notably Hornady and Buffalo Bore. A blog post which includes the latter ammo out of my 94 Winchester AE can be found here, with subsequent posts here and here.

And lastly, there’s another cartridge we tested which really should be included in the “magnum” category, because it sees the same increasing power levels out to at least 18″ of barrel: .45 Super. This proved to be more than a little surprising, since it is based on the .45 ACP cartridge.  Most semi-auto firearms which shoot the .45 ACP should be able to handle a limited amount of .45 Super, but if you want a lever gun set up to handle the cartridge you’ll have to get it from a gunsmith.

 

Jim Downey

April 2, 2017 Posted by | .22WMR, .32 H&R, .327 Federal Magnum, .357 Magnum, .38 Special, .41 Magnum, .44 Magnum, .45 ACP, .45 Super, .450 SMC, Data, Discussion. | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 3 Comments

Ammo test results for a pair of 1911s

This is the second in a series of informal blog posts about the .45 ACP/Super/.450 SMC testing sequence we conducted over the Memorial Day weekend. You can find the previous post here.

Today we’re going to see what the results are for a couple of different high-end 1911 platform guns. The first is an Ed Brown Kobra Carry (reviewed here), a Commander-sized (4.25″ barrel) single stack designed as a concealed-carry gun. We made no modifications of it for the more powerful loads. Here it is during our testing:

Ed Brown

The second is a Wilson Combat Hunter set up for the .460 Rowland cartridge with a 5.5″ barrel. Here’s my review of it, and here it is on the day of testing:

Wilson hunter

As I said with the other two posts about these tests, it’ll be a while before we have all the data crunched and the website updated, but I thought I would share some preliminary thoughts and information through a series of informal posts.

Quick note about the data below: All the ammo used, with the exception of the four * items, were part of our overall test sequence and had three shots made over the Oehler chronograph (which is a double-unit, and automatically records and then averages the two readings), representing a total of 6 data points. I’m just giving the overall averages here; the full data will be available on the website later. The four * ammunition types only include two shots/four data points through the Ed Brown Kobra Carry,  since it is a typical length for a self-defense gun. That’s because we only had one box of each of this ammo, and were wanting to get data which would be of the greatest use to the largest number of people.

Ammo                                                         Ed Brown Kobra Carry              Wilson Combat Hunter

      Buffalo Bore

.45 ACP Low Recoil Std P 185gr FMJ-FN                 798 fps / 261 ft-lbs                       791 fps / 256 ft-lbs

.45 ACP Std P 230gr FMJ-RN                                811 fps / 335 ft-lbs                       819 fps / 342 ft-lbs

.45 ACP +P 185gr JHP                                       1130 fps / 524 ft-lbs                     1139 fps / 532 ft-lbs

.45 ACP +P 230gr JHP                                        952 fps / 462 ft-lbs                       970 fps / 480 ft-lbs

.45 Super 185gr JHP                                         1257 fps / 648 ft-lbs                     1312 fps / 706 ft-lbs

.45 Super 200gr JHP                                         1175 fps / 613 ft-lbs                     1216 fps / 656 ft-lbs

.45 Super 230gr FMJ                                         1067 fps / 581 ft-lbs                     1105 fps / 623 ft-lbs

.45 Super 230gr JHP                                         1084 fps / 600 ft-lbs                     1109 fps / 627 ft-lbs

.45 Super 255gr Hard Cast                                 1061 fps / 637 ft-lbs                     1074 fps / 653 ft-lbs

      Double Tap

.45 ACP +P 160gr Barnes TAC-XP                        1121 fps / 446 ft-lbs                     1162 fps / 479 ft-lbs

.450 SMC 185gr JHP                                          1310 fps / 704 ft-lbs                     1350 fps / 748 ft-lbs

.450 SMC 185gr Bonded Defense JHP                  1254 fps / 645 ft-lbs                     1294 fps / 687 ft-lbs

.450 SMC 230gr Bonded Defense JHP                  1103 fps / 621 ft-lbs                     1108 fps / 626 ft-lbs

      Hornady

Critical Defense .45 ACP Std P 185gr FTX               969 fps / 385 ft-lbs                       976 fps / 391 ft-lbs

Critical Duty .45 ACP +P 220gr Flexlock                  932 fps / 424 ft-lbs                       936 fps / 427 ft-lbs

      Underwood

.45 Super 170gr CF                                           1249 fps / 588 ft-lbs                     1259 fps / 598 ft-lbs

.45 Super 185gr XTP JHP                                   1285 fps / 678 ft-lbs                     1339 fps / 736 ft-lbs

.45 Super 230gr GD JHP                                     1071 fps / 585 ft-lbs                    1099 fps / 616 ft-lbs

*Federal  HST .45 ACP Std P 230gr JHP                815 fps / 339 ft-lbs

*G2 Research  RIP  .45 ACP Std P 162gr JHP        961 fps / 332 ft-lbs

*LeHigh Defense .45 Super 170gr JHP               1165 fps / 512 ft-lbs

*Liberty  Civil Defense .45 ACP +P 78gr JHP         1843 fps / 588 ft-lbs

As with the other guns I’ve posted about, the general trends are pretty clear with the power rising as you go from standard pressure to +P to Super/.450 SMC, and topping out at about 750 foot-pounds of energy in a couple of loads. And it is interesting to note that the 185gr loads seem to be the “sweet spot” in terms of power across the board.

Of course, pure power is just one component for what makes a good ammunition choice. Bullet design & penetration is extremely important when considering a self-defense load. Shootability in your gun is also critical — because if you can’t recover quickly from shot to shot, then you may limit your ability in a stressful situation. Likewise, if the ammo doesn’t function reliably, or damages your gun, that is also a huge factor.

Most of the ammo we tested functioned very well in both 1911 platforms.  Interestingly, while we had experienced FTFs (failure-to-fire) with a number of the different Double-Tap rounds in both the Bobergs and the Glocks, we didn’t experience any such problems with either 1911.

The larger platform of the Wilson Combat Hunter handled the recoil very well, even from the hottest loads. Recoil was a little more noticeable with the Ed Brown, but only by a slight amount. As I noted with the Glock 21 converted for the .460 Rowland,  I was impressed that The Wilson Combat Hunter didn’t have any problems cycling even the lightest loads reliably.

Another note: we were unable to detect any damage or unusual wear to either gun, though it is possible a steady diet of loads of that power could cause some over the long term.

Lastly, I ran some .460 Rowland Buffalo Bore 230gr JHP cartridges through the Wilson Combat Hunter, since we had only had one type of ammo for that gun when we did the .460 Rowland tests.  That had been Cor-Bon Hunter 230gr JHP. The Cor-Bon tested at 1213 fps / 751 ft-lbs, and the Buffalo Bore tested at 1349 fps / 929 ft-lbs of energy.

Look for more results, images, and thoughts in the days to come.

Jim Downey

June 9, 2015 Posted by | .45 Colt, .45 Super, .450 SMC, .460 Rowland, Data, Discussion., General Procedures | , , , , , , , , , , , , , , , , , , , , , , , , , , , | 3 Comments