Wednesday, June 08, 2011

Trade-Offs - Gun Power

Okay, one more gun post and I'll shut up about that for a while.

 Lot of guys out there know way more than I do about boomware, but I can sometimes translate it to a lay audience better.

We've mentioned that in gun power, bullet size matters. (So do velocity and projectile composition.) 

So do the sizes of the slugthrowers.

The quick-and-dirty stat is this: Bullets come out of short barrels slower than they do long barrels, all things else being equal. This sounds counter-intuitive, but it's not, and here's why:

When the gun goes boom! expanding gases from the exploding gunpowder kick the bullet out the barrel.

As soon as the bullet and gases clear the muzzle, the marriage is on the rocks. The bullet goes on his way, the gases disperse, and it's Adios, bulleto.

With a longer barrel, the gases push the bullet longer in time, and thus faster. 

So it is that a two-inch snubbie won't send it to the same velocity as a 4" standard barrel or a 6" target barrel. And a rifle in the same caliber will beat a pistol.

Pistols are trade-offs by nature. They give up knock-down power for a) portability and, in today's world, b) the ability to conceal a weapon. 

If I were counseling you on a home defense weapon and you knew very little about guns? I'd tell you to get a 12-gauge pump shotgun. Lot of reasons, not the least of which is the sound of the round being chambered, chonk-chonk will scare the pee out of anybody who hears it and knows what it is. 

Hmm. Maybe that house down the street would be a better place to burgle if some fool with maybe an itchy trigger finger is coming down the hall with a fucking shotgun!

In the earlier discussion on mouse guns, I explained why smaller was sometimes more useful: Small gun in a situation requiring a gun is better than no gun.

I prefer revolvers, but a two-inch J-frame snubnose with most ammo has a single-shot stopping rate of around 66-68%. What this means is, you shoot somebody one time to the body, they cease and desist that many times out of a hundred. (There are ammo exceptions, but let them be for now.)

Best fight-enders among common handguns: .357 Magnums and some of the .40 S&W's and hot-loaded 9mm's. Nobody knows what a .500 Max will do 'cause nobody's gotten shot with one yet, and some of the .44 Magnums go right through before they expand, without dumping most of their energy into the target. You still don't want to get shot with one, and if the bad guy has seen Dirty Harry, that might go a ways to calming him down. 

With rifles and expanding bullets that dump big energy into a target, that number approaches 100%, though it's kind of like Zeno's Paradox about Achilles and the tortoise ...

Let that go. Also let go the notion that you get into a gunfight and you are only going to shoot somebody one time and then look carefully to see what he does next. Come the moment and somebody charging you with a knife or baseball bat or shooting at you, unless you are carrying a cap-and-ball dueling pistol, you are going to shoot more than once, and to one of two ends: A) The assassin charging you falls down and desists from further aggressive action, or B) You run out of ammo. If you hit him all those times and he keeps coming? Throwing the gun probably won't do you any more good than it would throwing it at Superman. 

Guns are not magic wands. They don't always stop everybody every time. 

I haven't seen the statistics on the increase or decrease in stops if you shoot somebody two, three or nineteen times, but in my heart, I believe that the more lead downrange that connects, the more likely that a stop will occur, adrenaline-fury and PCP notwithstanding. 

Back to the J-frame. So this is a five-shot revolver and with the best ammo, probably around a 68% stopper. 

The .380 ACP mouse gun is actually a slightly better one-shot stopper, the best rounds at around 70%. 

Why? Generally, the barrels are a bit longer, and the action allows less of the propellant gas to escape than a revolver's cylinder gap, so the bullet, which is essentially the same diameter as the .38 Special,  scoots out a little faster than the snubby generates.

Another trade-off here is that semi-autos in this caliber are finicky about ammunition and will sometimes jam. Generally, it is considered a good idea to fire 200 rounds through any pistol you plan to carry for defense, and until you find a round it will do that with without any jams, you don't trust it. 

.380 ACP ammo is expensive. It might cost you a couple hundred bucks to get something your gun loves. 

A pistol that jams on the second round is the same as dueling pistol. You don't have to do as much to maybe get a second round chambered, but you might have to rack-and-tap, and you have to do something.

Mostly with a J-frame revolver, you give five for sure.

Then again, if you find one a .380 that works for you as it should, you usually get six or seven cartridges, sometimes even 7+1, which is three more than the J-frame, and you can carry it in your jeans pocket ...

Decisions, decisions. 

I hope I cleared this up for you ...


Captain Tightpants said...

Not to hijack sir, but two things that I think are important to add:

#1 - the primary issue with short barrel vs. long barrel in a pistol of any flavor is that of accuracy. The longer barrel is more accurate due to a variety of factors - number of turns, sight radius, etc. But any handgun is a compromise in size vs. concealability as you have mentioned.

#2 - Another advantage the semi-auto will give you over the revolver is that of a more rapid reload. While the five rounds out of a .38 are reliable, if you need more it is going to be slow getting back in the fight.

As you said though, some of the .380 autos are a bit finicky...

Don't sell short some of the 9mm sub-compacts as well.

Steve Perry said...

No question that the longer sight radius matters when it comes to lining up iron sights. And intrinsic accuracy is less, though for practical purposes at combat range, a snub-nose is capable of tight groups with practice.

I've seen a video of Bob Munden popping balloons at a hundred yards using a NAA mini-revolver in .22 LR.

Of course, he's a professional shooter, but obviously the gun is capable of it in the right hands. Oddly enough, there are shooters who can do better than a bench rest -- that onboard computer does some adjusting ...

I could keep 'em all on a man-sized silhouette target at fifty yards with my S&W Chief, with a 2" barrel if I wasn't in a hurry. In a rest, it would group them between 3 and 4" at twenty-five yards. Not a tack-diver, but certainly acceptable.

And laser sights and/or red dots have done some interesting things for short gun accuracy, too. It becomes a pointer.

I've had two .380 ACP pistols I wish I'd kept. One was an HSc Mauser Pocket Pistol, one of the first double-action pistols, the other an AMT Backup.

The Mauser was a post-war, circa 1965, and it was a tack-driver. Great natural pointer.

The AMT would eat any ammo I fed it and I can't recall ever having had a jam.

Steve Perry said...

No, wait, I sit corrected here: Munden was shooting at *two* hundred yards.

Captain Tightpants said...

Definitely not denying the potential with a trained shooter and practice - was just describing for the "average" person sir. In my experience 25 yards is about the outside effectiveness for MOST shooters with a handgun of any nature, and that's on a static range without the stress of movement, people shooting back at you etc. I also have worked with folks and units where we would shoot 10" plates at 50 yards for beer money - but our practice budget for ammo was a bit larger!

Even in fiction though, it's generally hard to justify most pistol shots beyond that range in the first place - in terms of a realistic threat & the best tool for the job. Though there are always exceptions...

I definitely agree on the improvements lasers and dots have brought to the snub gun arena - both in practice and in practical use. Nothing like watching a dot bounce around a target as you pull a trigger to realize if you're smooth or not, and the ability to pull & point and know where you're shooting at bad breath distance is literally a life-saver.

The Mauser HSc was on my "wish list" for years, but I never ran into one at the right time - always heard good things about them, and the ability to change calibers was ahead of their time.

Steve Perry said...

Curious, CT, because I haven't seen new stats lately, but back in the day, the FBI pegged the average gunfight as three-threes, that is, three shots, three feet, three seconds.

You know if that has changed, in re civilians?

Captain Tightpants said...

Can't answer 100% as to how it's changed law enforcement vs. civilian - the closest relevant stat I do know is that about 80-85% of gunfights (talking law enforcement and civilian both, not military engagements) take place at 7 yards or less.

Other important elements - which I can not only say are matched by published statistics but by my own experience in seeing this stuff over the years: The vast majority of rounds fired miss; and the "one shot stop" is a rare beast indeed. Of course, certain things skew those numbers but in general folks who expect a single round from a handgun to end things are in for a rude surprise. Your 3/3/3 example would be relatively appropriate though from what I've seen - it's quick, it's violent and it's done one way or another. Though more often than not the parties survive, due to the quality of modern medical care.

Which is why I teach (along with those I've studied under, who have a far more impressive resume then I will ever approach) that you shoot the threat all the way to the ground - don't plan on just one round, or a "double tap", or the Mozambique 2 to the chest 1 to the head or whatever other magic drill you've seen - you simply engage the threat with sustained, accurate fire until they are no longer a threat. Then you check for more threats and then reload and be prepared to work again.

I think (given my limited skills in that area) that it is no different in close combat using unarmed or blade techniques - I've never been shown the "one secret move" that will magically end the fight in any reputable training; instead I've always been taught that you use what you need in your toolbox until the threat is no longer able to hurt you, or has disengaged.

I'd be curious as to your thoughts on the above... how it meshes with the teachings of silat in the various forms.

Captain Tightpants said...

Also sir I have a separate question from my wife if I could have a moment offline at some point? sinapu at gmail if you please - if not, then I understand!

Steve Perry said...

I'm not a believer in the one-punch-kill philosophy, either. Sure, it might happen, but when I was doing my medical stuff, I rotated through the ER, and learned first-hand that people can be fragile or durable, and was amazed at some patients who came in under their own power.

I've seen folks with an ingrown toenail carry on as if their leg had been laid open with an axe. And people whose leg had been laid open with an axe who were calm and not in any great pain.

I've always believed that you applied your tools until the threat ceased, and better to have more and not need them than to need them and not have them.

I think the idea of the Mozambique Drill is to apply major force upfront, and it gives you a focus -- plus you practice head-shots -- but if you can make head shots, getting one of those in first would probably save you two rounds you might need elsewhere.

Anonymous said...

Very informative Steve! I personally only own and operate rifles. Not that I have any prejudice against handguns or anything like that, but I'm a hunter so I already have more than one rifle which I keep available in my closet in a gun safe in the event of an intruder or similar threat. A rifle may be bulkier and take more time to get ready and reload I know for a fact that one solid shot with a Wolf .223 cal. 55 - gr. FMJ from my Remington will put the attacker out of the fight one way or another.