Wednesday, September 25, 2013

Riot gun part 1: What ammo is best?

My thinking is that #1 buckshot is the best choice most of the time, though #4 buck has a lot to recommend it some of the time.

Today I'm launching a series that will be ongoing for some time. As I noted previously, my posts here will  be on a now-and-then basis. But I have a number of things to talk about on the topic of defensive shotgunning. Expect this to take a while.

For years and years, the 12 gauge riot gun has been my preferred 'preparedness' weapon, for potential use during some sort of hypothetical societal crisis, such as a general breakdown of law and order, or perhaps a zombie apocalypse. It is also what I keep on hand for home defense. I like the shotgun for its outstanding hit probability at short range. Since nearly all lethal force encounters, apart from the battlefield setting, are at short range, I don't worry very much about the shotgun's uselessness at long range.

I will be writing up a series of suggestions on how to use a riot gun efficiently. I am not an amazing shot, by any means, but I have paid attention to the craft of shooting and done so for a very long time. I have sought to understand what works and what doesn't. I will present things that have struck me as useful techniques and methods as, over the years, I have tried to understand how to make best use of my weapon. Try these tricks and see if they improve your shooting.

The Right Buckshot

The first of these tips I'll be offering is simple: Use the smallest shot size that will get the job done. This does two things for you. It maximizes pattern density, which is always useful, and it minimizes danger radius, which is sometimes useful. It is a bit of reasoning well proven in sporting uses of the shotgun, but the idea does not seem to be well understood in combat shooting. The famous double-ought buckshot that everyone is using is bigger shot than necessary for most uses, has a sparse pattern and carries lethal energy a whole lot farther downrange than you are likely to shoot at anything when using a shotgun.

In a previous post I talked about a nifty ballistic calculator, which is downloadable for free, that calculates the flight of round balls. Since buckshot is a bunch of round balls launched at the same time, you can use the calculator to check on the behavior of buckshot pellets in flight. Among the things the calculator will tell you is the energy remaining for a ball at various distances.

An old military estimate says that a ball needs a minimum of 58 foot pounds to inflict a lethal or disabling wound. That number was figured into the design of the famous claymore mine, and served as an artillery rule of thumb for many years before that. It is an easy matter to use the calculator to find out how far buckshot flies before the energy of each pellet falls below 58 foot pounds.

Using, then, the 58 foot pounds minimum and the Connecticut Muzzleloaders calculator, we take for our entering argument the nominal sizes of buckshot:

#4 -------.24 cal
#3 -------.25 cal
#2 -------.27 cal
#1 -------.30 cal
#0 -------.32 cal
#00 -----.33 cal
#000 ---.36 cal

To keep things simple I'll look at just one muzzle velocity, 1250 fps, as that is about what's realized in fact by a lot of standard velocity loads marked 1325 fps or thereabout. Get the free calculator and run your own numbers for other velocities if you are curious.

Bad news for #4 buck. It has dropped to 58 foot pounds per pellet just nine yards from the muzzle.

That may explain the spotty reputation of this load. It gives you good pattern density but the pellet energy is not very good at a distance. Sizes #3 and #2 are of only academic interest, since the manufacturers aren't loading those sizes in 12 gauge shells. If anyone is interested, the calculator says that #3 is down to 58 foot pounds at 17 yards and #2 carries 58 foot pounds out to 38 yards.

Number One Buck, with its .30 diameter and nearly twice the mass of #4 buck, does a lot better, reaching out to 76 yards before the energy drops to 58 foot pounds.

And now the famous 00 load. That gets out a little past 115 yards.

For size 0 the distance is a little over 100 yards. For 000 it is 160 yards.

58 foot pounds is not very much; it is comparable to the much despised .25 ACP. The shotgun, though, is launching multiple projectiles, which makes a big difference.

It is, of course, unlikely that you will hit anything that you intend with buckshot at 115 yards. That raises a safety concern. To what purpose, then, does 00 carry lethal energy out to 115 yards? Bear in mind, too, that the 58 foot pounds figure is not a magic number, below which projectiles are harmless. A much less energetic projectile than that can kill, if it hits someone in exactly the wrong place. Safety concerns, therefore, are not adequately addressed by supposing that, when the energy falls below some magic number, the projectile is no longer deadly. A pellet is safe when it has stopped. But we can say that a projectile that has less energy, when it flies beyond the distance at which it might reasonably be used, represents, comparatively, less of a threat.

My thinking is that #1 buckshot is the best choice most of the time, though #4 buck has a lot to recommend it some of the time. 00 is surely not a bad load, or it would not have gained its good reputation and enduring popularity. It is, though, bigger than it needs to be.

 #4 buck is a great load so long as you are sure that, should threats appear, they will be close. This test shows nine inches of penetration into ballistic gelatin at 50 yards, well short of the FBI's recommended penetration minimum of twelve inches. While the shot is still dangerous at 50 yards it may fail to be decisive. The energy falls well below 58 foot pounds; as I said it's not a magic number, but the clear result is that there are limits to how far you can shoot with this load and expect it to work properly.

#4 buck is, though, fine for most home defense scenarios, for they occur at much shorter distances than 50 yards, and it gives outstanding pattern density. Because it loses energy fast, this size bears consideration for use in built up areas where you have concerns about danger radius.

00, the de facto standard, of course has plenty of pellet power for as far as you can hit with it, but it is dangerously energetic for farther still.  #1 buck is not as dangerous as far. It also comes close to splitting the difference in pattern density between #4 buck and 00. Depending on brand, #4 buck shells hold from 21 to 27 pellets; 00 shells hold eight or nine. The available #1 loadings are 15 or 16. There was a 20 pellet #1 load but I have not been able to find it for sale  for several years. It was never highly popular because it has quite a kick. It's not a lot of fun to shoot. I'm saving what I have left for a zombie apocalypse.

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