Welcome to the G.A.P - Handguns

Guns Magazine, May, 2004 by Massad Ayoob

The 2003 introduction of the Glock 37 pistol brought with it a proprietary cartridge, the .45 GAP (Glock Auto Pistol). It resembles a shortened .45 ACP round, though there's more to the design internally than that. It also brought some speculation. I've heard again and again, "Why the hell do we need a new .45 auto cartridge?"

The main answer is hand fit. The larger frame pistols Glock produces in .45 ACP--the full size G21 and the shorter G30 feel "fat" to many shooters' hands, and require a fairly long reach to the trigger. Glock does offer the slim-lined G36 .45, which solves those problems nicely, but that gun's six-round magazine is a turnoff for many buyers, who equate "Glock" with "firepower."

Until now, the answer has been to customize the grip frame by filling the hollow at the back with epoxy, and then trimming the whole thing down. Pioneered by Robbie Barrkman of The Robar Companies, this process has become known as Robarizing. It only has two downsides. First, it comes with a three figure bill. Second, a major concern for police departments, such alterations void the factory warranty on the frame.

By creating a .45 auto round with a shorter case, Glock and CCI/Speer were able to reduce overall length sufficiently to operate ill a pistol whose frame was sized for the shorter 9X19 cartridge (and .40 S&W, and .357 SIG). This resulted in increased pressures. At first hoping to be able to keep the slide dimensions of the 9mm G17, the Glock engineers soon realized that this higher-pressure big bore would need a more massive slide. As a result, the G37 comes with a slide about as thick across as a G21's or a G30's.

This in turn protrudes out over the standard low-profile Glock slide lock lever, so the G37 is provided with the larger level developed originally for competition use in their Tactical/Practical models, the 9mm G34 and the .40 caliber G35.

As on other Glocks so equipped, I found that if I shot right handed with the currently popular straight thumbs position, my thumb would either bump the lever up and cause premature slide lock during cycling, or over-ride it and keep it from locking the slide back when the G37 ran dry. Returning to the old, reliable low thumbs grasp solved the problem. Because of the wider slide, it probably won't fit your smaller caliber Glock's holster, but seems to work fine in a G20 or G21 scabbard, and the mags will fit a Glock 17 size pouch.

Power Up

Historically, a shorter cartridge of the same bore diameter tended to be less powerful than the longer version. The .45 Schofield seemed anemic in comparison to the longer .45 Colt in the days of the Western frontier, and the 9mm Short (9mm Kurz, .380 ACP) is a much weaker sister to the 9mm Luger, whose case is 2mm longer. This tradition has, happily, been broken by the .45 GAP.

We chronographed it with all three bullet weights currently available. It had been thought at first that for pressure reasons, only 185 to 200 grain bullets would be viable, but Winchester figured out how to load it with the full 230 grains of bullet that .45 auto traditionalists expect. "Our company learned a lot about managing high pressures in small casings in developing the WSM (Winchester Short Magnum) rifle cartridges," Winchester's Paul Nowak told me.

185-grain Federal Hydra-Shok was particularly consistent and ran well over 1,000 feet per second, outperforming most standard pressure .45 ACP loads in that bullet weight. 200-grain flat point CCI Lawman .45 GAP averaged 999.6 fps, distinctly faster than 200-grain Lawman .45 ACP out of a G21 of similar barrel length.

Winchester's 230-grain ball round was in the same ballpark (no pun intended) with classic GI .45 hardball, the GAP round averaging 824.5 fps. Winchester's high-tech Ranger-T JHP 230-grain from the .45 GAP averaged a hot 866.7 foot-seconds. Only if you go to a P loading will the .45 Automatic Colt Pistol cartridge run the same bullet taster than a .45 GAP.

Job One

As the old Ford ads said, "Quality is .lob One." That includes reliability. The very first run of G37 magazines had an oversize follower that could hang up on the breechface when the gun went empty, and before the slide lock lever could engage. This meant you had to pull the empty mag out by force, causing the slide to close on an empty chamber. Glock quickly corrected that with a re-dimensioned follower (and will replace early magazines for free) and cured the problem. Other than that, several friends anti I have fired thousands of rounds of Federal, Winchester, and CCI/Speer ammo (mostly the latter) out of about half a dozen Glock 37s with zero malfunctions. Job One is accomplished.

Accuracy is typical of standard frame Glock service pistols: 2 to 4-inch five-shot groups at 25 yards. I've not yet seen cmc of those gilt-edged 1.0" or 1.5" groups that we often gel with .45 ACP out of G21s and G30s. Recoil is snappy but manageable.

The Glock 37 and the .45 GAP cartridge work. The GAP round will expand its popularity when smaller pistols become available for it, which should be any time now.