Stoking the GAP: reloading the .45 GAP is a SNAP

Guns Magazine, May, 2005 by Charles E. Petty

The premise of the .45 Glock Automatic Pistol is to provide the ballistics of the .45 Automatic Colt Pistol in a smaller platform. The .45 GAP cartridge case is .138" shorter than the .45 ACP and the overall length more closely matches the .40 S&W. The goal of the .40 S&W was to put a major-caliber cartridge in a 9mm frame. This time it is to put a .45 in a .40-size pistol.

I think it would be fair to say that the .45 GAP was met with a fair share of skepticism. "That can't be done." was heard more than once. The efforts of the cartridge case designers, largely Speer and Federal, gave us a case that is not simply a shorter ACP and they proceeded to load it with 185- and 200-grain bullets of both FMJ and hollowpoint designs. But when Winchester got aboard and showed it really was possible to duplicate the standard 230-grain load in the smaller case, interest seemed to improve.

If you compare it with the ACP, you first will see it uses small pistol primers. The reason is exactly the same as it was for the .40--to avoid any possible interference from the ejector. With a large primer there was at least the potential that a cartridge might be ignited if a live round was forcibly ejected. You will also notice that there is a difference in the shape of the extractor groove on the cases. The GAP's groove is sharper, which means the web of the case is thicker. That, coupled with the small primer pocket equals a stronger case. The pressure limit is the same as the P .45 ACP (23,000 psi), but when you see the available case capacity is reduced by over 20 percent, powder selection is a serious concern. At first the opinion was the 230-grain load wasn't going to be possible, but Winchester showed the way there and both their 230-grain loads are effectively equal to the ACP. More recently, Remington announced that they, too, would offer 230-grain loads.

So let's lay one thing to rest right away. The .45 GAP can, and does. duplicate the ballistics of the .45 ACP. The cartridge is the real news here, for the pistols don't look or feel any different from other models. This then becomes a philosophical issue rather than one of ballistics and we go back to the age-old debate of whether or not you can put a 50-pound cat in a 25-pound bag. The GAP follows a well-worn path paved by the .40 S&W, which put a 10mm-size bullet in a 9mm-size pistol. Don't forget the first somewhat faltering steps of the .40 when folks thought that all you had to do was put a bigger barrel in a 9mm. There was more recoil and some delicate balancing was required to make slides just a little heavier. We will see the same thing here.

For the purpose of this test, I chose a Springfield Armory XD. Since it has a conventionally rifled barrel and fully supports the cartridge case, it is an ideal tool for investigating a new handloading challenge

There are many questions to answer:

1. Does the test firearm function well?

2. Does it duplicate the .45 ACP ballistics?

3. How does the accuracy compare to the .45 ACP?

4. How does available factory ammunition perform?

5. Is it possible to duplicate factory amino with handloads?

6. Is it possible to produce good "plinking" or target handloads?

A good variety of factory ammunition was available with bullet weights of 185, 200 and 230 grains in both hollowpoint and ball configurations. The XD functioned perfectly with all of them. Since we have no history with the cartridge or specific match-grade pistols, there is no easy way to compare accuracy, so it occurred to me to shoot some GAP amino in a revolver of known accuracy. That's not a direct comparison, but ought to provide a good clue.

As you can see from the chart, there is little left to be desired in terms of accuracy and there seems to be no penalty associated with the shorter case. It also shows us that the revolver's accuracy is not troubled either. Some preach that accuracy will be worse in a .357 Magnum when shooting .38 Specials. That has never been my experience, nor has it been so with .44 Special/Magnum and now .45 ACP/GAP.

Bullet performance?

Gimme a break! If we have the same bullet--we do--at the same velocity--we do--what's to worry? Tons of gelatin have been slain with Gold Dot and Hydra-Shok bullets and my experience with Winchester's Personal Defense loads has been good, too, so the key now is--as it has always been--where you put the bullet, not whose name is on it.

Handloading has been a bit more complicated. As is often the case, Hodgdon was first to publish some pressure-tested loading data, but they did not go above 200-grain bullet weights. Winchester followed quickly with data that did. Glock's prohibition against lead bullets doubtless influenced Hodgdon and Winchester to omit cast bullets from extensive testing. Hodgdon only shows data for the odd little 150-grain LSWC. But since we are not interested in hotrod loads I really wasn't too concerned about working out some moderate loads with 200- and 230-grain cast bullets. We've got lots of history with those in the .45 ACP, so if we take the 20-percent smaller case capacity into consideration for a starting point, all should be well. And so it was, although it took a tad more to get reliable function in the XD. Target velocities of 750 to 800 fps were easily and safely reached, but since we do not have the benefit of pressure tested data it's best to consider those as inflexible for now.