Tuesday, October 30, 2007

Does it really make much difference; or even much sense?

So, I kinda want one of these:



As a companion piece to the gift from the gods of boom. That, specifically, is a Dan Wesson Bobtail Commander, in 10mm

It's essentially a Dan Wesson frame (sorta... they are owned by CZ-USA but they do have their own factory in upstate New York.. unfortunately not the same factory they USED to be in in Palmer MA, but that facility was obsolete) with Ed Brown hard parts. The ones I've handled are excellent quality, and they just feel good in the hand.

Now, I really like the bobtail grip (though some very much do not, you need to try it first), and I've opined before that the commander length is my favorite 1911. Plus, much as I love my 5" 10mm, it is just a bit big for concealed everyday carry in Arizona (whereas I have no problem with my commander).

Now, a lot of folks think that in a 1911, the length of the butt is more of a problem than the length of the barrel. Those folks don't have rib cages like beer kegs.

I can (and have), quite literally, carry an MP5 under my arm. and not have it sticking out, so a fullsize butt on a 1911 isn't an issue; and the bobtail makes it even better (taking off the one major snagpoint in fact). Besides, I like to carry IWB; which tucks the butt in tight. It also puts the barrel lower than in other styles of carry, and therein lies the rub (literally).

Anyway, I think that would be a great companion piece as I said (and will complete the trifecta when I get a MecTec CCU to have a 10mm carbine as well).

Well, a few days ago a reader asked "Why bother with a 10mm from a 4" barrel. Wouldn't it just be a more expensive .40S&W at that point?"

Sadly, that's not a bad question. Why do I say Sadly? Well, because it SHOULDN'T be that way, but with much of the factory loaded 10mm out there, it is. Most factory defensive 10mm is basically loaded to +p .40 S&W levels; excepting the Winchester silvertip.

So, first, the good (as far as factory loads go anyway):

For comparison, the 10mm 175gr silvertips out of a 4” barrel will develop appx 1200fps and 559 ftlbs (about 50fps more from a 5"). The .40S&W 155gr silvertip develops 1200fps out of a 4” barrel, for 495ftlbs. With a 20gr mass difference at the same velocity… that energy difference is significant, but not overwhelming.

What IS a big difference though, is the penetration through 4 layers of denim. In a controlled expansion premium hollowpoint, that 10mm load will consistently penetrate 12"-14" of ballistic gelatin through denim. The .40 will only consistently penetrate to 9-10”.

Now, the bad... With any major factory load other than the silvertips , the numbers are downright depressing. When I said most was only at +p .40 levels I wasn’t kidding. The 180gr Federal Premium personal defense 10mm only manages 1030fps from a 5” barrel for 425 ftlbs. Their STANDARD pressure 180gr .40 load makes 1000fps for 400ftlbs. And that's before you account for the 4" barrel (You’ll typically lose about 50fps going down to a 4” barrel).

Most of the other major companies offerings are similar; following the general trend of the last few years with factory ammo de-magnumizing magnums (this is a reversal of the previous 60 years or so of trending the other way). It seems that once the "FBI load" came out and sold better than their previous full power loads, the factories took that as a sign that nobody really wanted a 10mm, they wanted an expensive .40S&W. Seems silly to me, but hey, I don't run the universe.

Back to the good news; there's a way around that problem. Go to a company like Doubletap, where they actually load close to a cartridges potential; and it’s an entirely different story.

The Doubletap 10mm 180gr controlled expansion rounds will do about 1300fps from a 4” conventional rifling barrel (a bit more from polygonal, and about 1350fps from a 5") for 675 ftlbs. The .40 s&w 180gr controlled expansion round will do 1100fps from a 4” barrel for 484 ftlbs.

Now THAT is a huge difference.

Doubletaps load, also happens to duplicate my best 10mm handloads (with the same bullet in fact); 180gr Hornady XTP at 1350fps (from a 5") and 729ftlbs.

It's good to know that there's still a way to get the performance you're SUPPOSED to be able to get from a gun, even if you don't handload (or if you don't want to use handloads for defense).

So, does it make sense to have a 4" barreled 10mm?

Sure... at least as much sense as it makes to have any 10mm at all. Or any other high intensity chambering for that matter. I have two commander length .45s (a custom commander, and a USP compact) and a revolver that are chambered for .45 super; none of them "make sense" much either, in terms of "needing" that much power to stop a badguy.

The .45 super isn’t a round that makes much sense, the 10mm isn't a round that makes much sense... heck, I’ve had a couple .357SIGS and they don't make much sense either. I love hot, high pressure rounds; but honestly, for shooting badguys, neither is necessary.

Handguns are handguns, rifles are rifles; until you get to rifle level ballistics, you’re never going to get MUCH more effective than .357 magnum or +p+ 9mm, or +p+ .45.

You’ll get a little bit more badguy whacking power from the much hotter loads, but not a huge amount. There's a small jump from +p+9mm to +p .40; then another small jump from +p .40 to +p+ .45; and another small jump to .45 super, and another to 10mm (actually, they're very similar in ballistic performance when loaded in the same weights).

Added up in total; the difference between a +p+ 9mm and a 10mm is about 55gr in weight, and the same velocity, for about 200ftlbs more energy. In handgun terms that's a lot, but from about 500ftlbs of energy (the floor of what I consider acceptable duty loads), up until you hit somewhere around 1250 to 1500 ftlbs of energy (depending on bullet mass, and design - basically hot .44 magnum level); the difference in wounding capability is actually pretty small.

Yeah, the 10mm is going to do the job better than the +p+ 9mm, but in comparison to a rifle, or a high intensity magnum hunting load (which most people wouldn't really want to carry on the street).... well, they might as well be the same.

'Course, just because it isn't strictly necessary, doesn't mean I don't want that little edge, or that I don't prefer the shooting feel of the 10mm to most other chamberings. It just means it isn't particularly practical or necessary.

The only particularly practical thing about either, is for use on other than humans. I like .10mm for walking in the woods, because you DO get more penetration out of it from a 5” barrel than the hottest .45acp; and for four legged furries, you can use that extra penetration. Same with .45 super (though .45 super really needs at least a 5" barrel to perform to potential and is better with 6"; because it has a relatively fat and heavy powder column).

Personally though, I just enjoy shooting the hot stuff. It's fun. Not only that; I find that in general I can shoot hotter rounds, faster and more accurately, than I can slower rounds. This flies in the face of convention, but it's true; I think because the faster round cycles the weapon faster.

So is the 10mm not much better than a .40?

Depends on what you mean by better I guess.

If it doesn't make much sense, and isn't all that much better, why do I shoot 10mm?

Because I can.