What is the difference between .45 ACP & .45 GAP calibers?

I'm interested in a handgun that shoots the .45 caliber. I'm not exactly sure what .45 GAP is and all I know is that .45 ACP is auto. From the guns I looked at, the .45 ACP gives a couple to a few more rounds, but what exactly is the difference between .45 ACP & .45 GAP? Is one more preferable than the other for different uses? This .45 caliber gun will mainly be for self defense, but also for some fun at the shooting range.

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  • Mac
    Lv 6
    1 decade ago
    Favorite Answer

    .45 ACP is the original. .45 GAP is a recent invention by Glock to have a .45 built on the same frame as the 9mm/.40 line of pistols. Magazine capacity will be the same in the same sized pistols since the cartridges are the same width. You might have seen a larger .45 ACP magazine because it was probably in a larger pistol.

    The .45 GAP is shorter but designed to be roughly equal in performance. It looks as if it might survive, but you will never have the ammunition availability (and hence lower ammo costs) of the .45 ACP.

    Interestingly, Glock had to use the wider slide of the .45 pistols, even with the smaller frame from the 9mm/.40 pistols to make a .45 GAP pistol.

    Springfield Armory's first .45 XD was a .45 GAP, but I think it died a mercifully quick death. The advantages are a bit overrated, and I highly recommend the standard .45 ACP.

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  • 4 years ago

    There's more to the difference between 45 ACP, and 45 GAP than just length. The GAP's case is shorter than the ACP's case by .138" which makes it, roughly, the same size as a 9mm cartridge case. The 45 GAP round is, therefore, well suited to use in a thinner and more compact size pistol than the much longer 45 ACP ever could be. Frame width, however, remains the same. The bullet sizes are, also, different. The 45 GAP uses 185 and 200 grain bullets. The 45 ACP, typically, uses 185 and 230 grain bullets. At the present time it is not possible to use 230 grain 45 caliber bullets in a 45 GAP pistol - The chamber pressure would be just too high. Typical operating pressure for the 45 ACP is 19 - 21,000 psi. +P rounds can go up to 23,000 psi which, also, happens to be the almost the same operating pressure for 45 GAP which produces between 21 - 23,000 psi. (In other words, even with the use of a lower flash small pistol primer, the 45 GAP is already, 'maxed out' and has no room left to grow.) Interestingly, while these two cartridges have identical external case wall dimensions, the 45 GAP is NOT a, 'short' version of the 45 ACP, and shouldn't be used as such. It is NOT safe to fire GAP cartridges in an ACP chamber. Yes, it can be done, but not without significant personal risk. While the external case wall tapers are the same, the internal case walls are much different. If you cutback an ACP case to match the GAP's length, the GAP's internal taper is lost and 45 caliber bullets will bulge the case mouths when they are inserted. The case rims are, also, different. The GAP's rim is slightly rebated, and the extraction cannelure has a sharper angle to it. An ACP pistol's extractor might have a hard time consistently catching onto and digging into GAP rims. When it comes to recoil (and ease of recoil management) there's a significant difference to be considered: On the high end, the 45 GAP uses a 200 grain bullet launched at 21 - 23,000 psi and about 1,100 fps. The 45 ACP uses a 230 grain bullet launched at 19 - 21,000 psi @ and about 850 fps. That's a big difference! I have never shot the 45 GAP; but, I've been told that the recoil is very similar to a 40 S&W; and that statement seems reasonable to me. It, also, indicates that I'm not going to be running out anytime soon to pickup a GAP pistol. I'm very comfortable, very fast, and very accurate with the 45 ACP. Personally, I attribute a lot of this to the ACP's outstanding recoil characteristics. (And, to be perfectly honest, I have to suppose the 1,000 to 1,500 45 ACP rounds I fire every month, also, have something to do with my preference for and skill with this particular cartridge. Do I think the 45 GAP has much of a future in front of it? Well, people are people; and it wasn't too difficult for the, 'professional pistol users' among us to first gravitate to the new 10mm, 'wonder round' and, thereafter, to the new 40 S&W, 'improvement'. Yeah, I think it'll slowly catch on; but, at the same time, I don't see myself going along with the crowd. I've got my favorite CQB pistol cartridge; and, unless they come out with a new, 'photon laser', or some such, I really don't need the next new, 'wonder cartridge'. I'm fine with, and have a lot of confidence in, what I've already got.

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  • 1 decade ago

    The difference is that the GAP is about an average of 20 cents more per bullet. This can add up quickly! the .45 ACP is much more popular. If you are going to shoot a lot then go with the .45 ACP

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  • WC
    Lv 7
    1 decade ago

    The .45 GAP is Glocks way of trying to create the performance of the .45 ACP in a cartridge that would fit the popular Glock 17 frame size pistols.The .45 GAP round uses a small pistol primer, whereas the .45 ACP round uses a large pistol primer

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  • Anonymous
    1 decade ago

    In addition to what the first two posters said, if you look at the two rounds, side by side, you will see that the ACP round is taller than the GAP round. Velocity and energy are close but the ACP round still comes out on top. GAP is short for Glock Automatic Pistol.

    I considered the GAP for awhile when I replaced my old, tired Colt Combat Commander. I decided to stick with what I knew and now carry a .45ACP, Kimber Pro Raptor.

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  • MJ
    Lv 7
    1 decade ago

    Also, GAP can only equal non +P ACP that is in a lighter (say, 185 grain) bullet weight.

    ACP has the potential to make more power, and use a heavier bullet.

    GAP doesn't have enough advantages compared to its disadvantages to recommend over ACP.

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  • Anonymous
    1 decade ago

    In my rarely, if ever, humble opinion, its a gimmick, and a lame effort by Gaston Glock to have a cartridge named after him. The marketing fluff has something to do with a slightly shorter cartridge and a thinner grip. I guess he hasn't shot a lot of 1911's.

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