Wednesday, June 21, 2006

What to feed them, part II - .45acp

A reader on "The Other Side of Kim" asked: "I jsut bought an H&K USP .45. What ammo would be best for it".

Well thats a relatively complicated question, for one thing what do you want to do with the gun? The type of shooting you are doing determines the type of ammo you shoot with it. Also which USP is it (the compact, one of the full sizes, the tactical, the expert etc); but we can make some general recommendatios, both for the USP, and for other .45 pistols.

The most important factor in deciding on ammunition, is choosing a loading of adequate power, that your gun groups well with, and that you can control properly.

It is far more important to get ammo that gives you sufficient practical accuracy (4" groups or better at your maximum engagement range... usually 10-25 yards), then to have the most powerful load on the planet.

You must also be able to rapidly make accurate followup shots in case of failure to stop.

You can't miss fast enough to win, you can't miss hard enough to win; and winning in a gun fight means being the one not dead, so don't miss.

230gr FMJ (full metal jacket aka “ball” or “hardball” ) is fine for practice, but marginal for defensive purposes.

Various 185 gr or 200gr truncated cone, semi-wadcutter, and other solid tipped bullets are great for competition (and especially reloading for competition), but generally speaking arent what you want for defensive purposes unless your gun doesn't feed hollowpoints reliably.

Somehow however, I dont think a pistol competitor is going to be asking what to feed his new USP. Somehow I think we are talking about ammunition for serious social purposes.

For defensive purposes, in .45acp I strongly recommend a premium jacketed hollowpoint (JHP). They are available in weights from 165gr to 230gr, and in standard, +p and +p+ pressures (the higher pressure, the higher velocity for given weight); and with a premium namer brand JHP you know you will have at the least acceptable performance (presuming they group well).

The major brands of premium hollowpoint to consider are Speer Gold Dot, Federal Premium/Hydrashok, Winchester Silver Tip, Cor-Bon, Remington Golden Saber, Hornady XTP, and Winchester Ranger. There are other brands, and product lines from those brands, but those I mentioned make up the majority of the premium market; and I can personally vouch for their quality and efficacy in testing media.

Next, you need to determine your personal recoil tolerance. The lighter the gun, the more you will feeel recoil. The heavier a bullet, the more recoil you will feel for a given speed. The faster a bullet is moving, the more recoil it will feel for a given weight.

Too much recoil for you personally is subjective, but in my USP I don't find any standard +p or +p+ loads to be excessive.

Once you’ve discovered your recoil tolerance, you need to find a load that groups well with your gun. Buy a selection of loads that fit within your recoil tolerance, across a broad range of weights and velocities; and shoot for groups.

A gun may group roughly the same with any load you try; but that's fairly rare. The msot common situation is that you will find a few loads that group poorly, a broad range that group reasonably well, and then a laod or two that give you substantially better groups.

The mechanical (as opposed to environmental or operator) factors which effect group size are many and varied; generally significant are the weight, length, construction of the bullet, powder burn rate, charge weight, overall pressure, the length and rifling of the barrel, and the overall "tightness" of the gun. Of course the single most important factor is consistency. The more consistent all the major factors are, the more consistent your groups will be; and of course the same applies to the shooter.

Anyway, that's not all that relevant to our discussion, except to highlight a couple things:

1. Shorter barreled guns are generally more picky about load selection in general, both pressure and weight

2. Polygonally rifled barrels generally have a broader range of decently grouping loads, but are pickier about the best grouping loads. Polygonally rifled barrles are also somewhat more sensitive to pressure variations within a given weight range.

3. Groups will vary in size with the length and weight of the bullet (some guns like heavier, some lighter)

4. Groups will vary in size with the pressure of the load (some guns like harder, some softer)

6. Ammo with a similar construction, similar length and weight, loaded to a similar pressure and burn rate should group similarly; from the same gun.

Some guns have the perfect storm of ammo sensitivy going for them. For example the Glock 36 is a light weight, short barreled, polygonally rifled gun. From the oprators standpoint it has a short sight radius, and a stubby grip, making operator consistency more difficult from shot to shot. The G36 is a gun that will shoot acceptably across a large range of loads, but it will show great accuracy (which it is certainly capable of) only with a very few.

My personal experience was that the gun liked 185gr and 200gr +p and +p+ loads. In particular going to a 200gr handloaded hornady XTP +p+ tightened my 7 yard groups from 4-6" to under 2". On the other hand shooting standard pressure 230gr hardball, the gun would barely group.

Yes, thats what I mean when I say ammo sensitive; and should illustrate how important it is to find a load that performs well with your gun. It's also important to note that not only is every model different, but each individual gun is slightly different; so waht worked for me, may not work as well for you, or it may work better; thus why it is so important to test for yourself.

Once you’ve narrowed the list down to a few selections which you find group well, don't necessarily chose the one that groups best. Choose the heaviest, fastest load which groups well, and doesnt present excessive recoil to you.

Why the heaviest, fastest? Simple: it gives you the best chance of a disabling wound given a marginal shot, or a failure to expand. The heavier the load is, the better it will peentrate, and the more energy it will deliver. The faster a load is the better it will penetrate, and the more energy it will deliver; thus the heaviest, fastest load that groups well is generally the best choice.

But if energy is so important, why not go for the lighst fastest loads? After all the 165gr (or even lighter) loads can be pushed much faster than the 200gr lods; and the 165gr is still heavier and faster than the .40 S&w, and according to the books delivers more energy than the slower heavier loads...

Yes, thats true, there is more energy in those lighter loads; but there is less momentum, and the energy bleeds of faster. There may be more initial wound shock and a larger temporary stretch cavity (you'll see these terms in magazines), and those MAY stop the attacker faster, but they arent as RELIABLE a wounding mechanism as the heavier bullets.

At some point (actually at two fairly distinct point, 1500-1750fps and 2500-2750fps) velocity produces enough shock to become a more reliable wounding mechanism; but at .45acp velociy ranges, this jsut isn't the case.

This isn't to say that the light weight high velocity loads are bad, but the heavier high rpessure loads have proven over time and experirence to be more reliable stoppers than the lighter loads.

One proviso on that though; choose a load that hits 1000fps or more. It's another one of those breakpoints where a significant increase in damage occurs; somewhere between 950 and 1050fps. The slower, low pressure loads dont reach 950-1050 fps, but the 200gr and 230gr +p and +p+ do.

More specific now…

In my personal experience, the USP likes hot 185gr and 200gr loads; or VERY hot 165gr loads. Overall the USP does better with faster loads. My personal preferences are the 185gr+p gold dot, the 200gr +p gold dot, the 185gr +p hornady XTP, the 185gr+p cor-bon, and the 185gr +p federal permium (hydrashok).

If you find that the heavier +p loadings give you too much recoil, then get either the fastest 165gr load you can (cor-bon), or the heaviest fastest standard pressure loads you can (230gr gold dot or hydrashok).

My springfield champion, a 4" 1911 prefers the 200gr gold dot +p, the 185gr hydrashok +p, the 185gr and 165gr CorBon +p+ or +p+ handloads in the same range

I still ahvent found the best laod for my S&w 625 (5" revolver), but I've got some recommendations I'm going to try out.

I’ve written a BUNCH of posts about the subject, in varying detail; here’s a couple:

Basic Ammo Questions Part 1

Lies, Damned lies, and Ballistics

Serious Chamberings for Serious Purposes

Under Pressure