45 GAP, the Glock 37, & the Caliber That Should Have Been

This week, we are going to take a look at an odd one, and not just for historical reasons. I was able to procure a Glock 37 and 1000 rounds of ammo to feed it recently for $800. That is a used gun off the secondary market, but it was available and not badly priced. Considering how crazy the gun market has been, you could do a lot worse. Why could it be had at that price? Because a Glock 37 is chambered in 45 GAP.

What is 45 GAP, some of our younger audience may be asking? 45 GAP was a cartridge developed at the behest of Glock around 2002, to mimic the ballistics of 45 ACP in a small frame pistol. One could call it 45 Short and not be wrong. The principle was to make a 45 caliber cartridge that would be equal or close to John Moses Browning’s (peace be upon him) 45 ACP, the American standard since 1904. Which itself was built to mimic or exceed the 45 Long Colt, in a much shorter package that would feed from an automatic pistol. So basically it was attempting to evolve the American love affair with 45 caliber into a slightly smaller gun, which briefed really well. But didn’t ever really catch on.

If you look at the Glock 37, you could easily mistake it for a Glock 17. This is fortunate because there are only so many reviews we can write on a Glock. So imagine gripping a Glock 17, but when you look at the slide, it is more like a 45 ACP or 10mm. That isn’t quite true, as the G37 ( 45 GAP) is actually 4/100ths of an inch smaller than the G21 (45 ACP). But close enough. It is effectively like having a G17 grip with a slightly fat slide that throws 45 caliber projectiles. Which sounds pretty cool. So what happened?

That lends itself to a lot of conjecture. Personally, and I was around when the 45 GAP hit the market, it seems like Americans just didn’t want to have a 45 option that wasn’t a 1911. In the early 2000s, it was like you have a choice. You shot 9mm or 40S&W out of a plastic gun, or you shot 45 ACP out of a 1911. Striker fired pistols had nowhere near the market dominance they do now, and it was rare to see a Glock in the wild where I lived. They were making great strides in the LE market, but in many ways, the civilian shooter still preferred a 1911. Or a 9mm. And very rarely both.

The other thing working against the 45 GAP was timing. It was developed and got its SAMMI Spec in 2002 and hit the market in Glock pistols in 2003. Now it had a good chance of taking over in a world of 10 round magazines. Which is what we were all stuck with around that time. Kids today will never know the pain of paying $100 for a SINGLE drop free high-capacity Glock 17 round magazine. (They might soon actually, given the state of the economy. But not the point.) Back during the “assault weapons ban”, that was common. If you could find one. Every magazine made before 1994 was grandfathered and therefore legal. And once again, Glock wasn’t all that popular in 1994. Ergo, there were not container loads of hi-capacity mags floating around, including 15 aftermarket suppliers.

I don’t think any of us expected the AWB ban to actually sunset in 2004, but it did. Overnight, you could purchase grown-up magazines again as long as you didn’t live in NY, Taxachussets, or Commie-fornia. The 45 GAP had been developed in the 10 round magazine era, and probably never engineered to get more. Now let’s say you are Glock, and the ban has just expired. You have machines that can turn out magazines all day and night for a hungry public. You have the prints in front of you for hi-capacity 9mm and 40S&W magazines. Do you hit the go button on things you already know how to make, or do you devote R&D time to maybe getting the 45 GAP up to 13? Me too. And as far as I know, to this day, no one makes a 45 GAP magazine that holds more than 10.

The 45 GAP did see some initial success, most famously as the weapon of choice for the NYPD. But it seemed like it was never enough. With 9mm, 40S&W, 45 ACP, and 357 SIG battling it out, there really wasn’t room for a 5^th. As time went on, and 45 GAP didn’t get more traction, ammunition slowly got more and more expensive. Which made it even more unpopular. As far as I know, only one other gun was ever chambered in 45 GAP, outside of Glock. Springfield Armory had a single model of original XD in 45 GAP, which is very hard to find.

This isn’t even my first rodeo with 45 GAP, though it is my first time shooting it. A few years back, I borrowed a G37 from Glock. But when I went to source ammo, Federal had some bad news. They made 45 GAP exactly once a year, to fill the needs of the NYPD, who still issued G37’s. I would have to wait a full year, so the G37 went back to Glock unfired.

So why are we talking about it now? Because the relative scarcity of guns and durability of ammunition have made it an absolute outlier. Even when ammo was absolutely nuts, 45 GAP seemed inflation-proof. When 9mm was approaching $1 per round, you could find 45 GAP at 40 cents all day long on AmmoSeek. There were a lot of cases of ammo bought by distributors that have been gathering dust on the shelves for years. This means it is a very viable option if you are way late to the party of getting armed. Or arguably, want to train with a Glock pistol but not pay 9mm prices.

How does it perform? Well, I am very happy with mine. It feels pretty much like 45 ACP recoil but has a 9mm handle to hold onto. Modern powders have caught the 45 GAP up to true 45 ACP speed and beyond, with a full 230-grain bullet. The G37 actually has mag bodies the same size as a G17, that isn’t an exaggeration. Which is pretty cool. It’s a strange beast, but it has really grown on me. To the point I am thinking about adding a few thousand more freedom seeds to the basement, the G37 needs to eat. If you want one of your own, get it while the getting is good.

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