ACP and GAP

[Skewed]

Hello,
I have been reloading .45 ACP for several years now for use in my 1911 and all has been fine. Yesterday, I went to the range and gave some of my reloads to my dad to use in his Glock. For the most part they did fine but he jammed a few times. Is there any significant difference that I need to take into account for this? My initial thought is that I may need to tighten the tolerances up a little bit.

Personally, I think there may be an issue with his firearm but I am not completely convinced yet as to if it is him or me. I have also noticed that his gun will sometimes not fire the round either. When this happens there appears to be a more than significant impact dent on the primer but it does not set it off. Giving it another try will set it off, I even took one and put it in my gun and tried it and it fired the first time, but with two dents in the primer when ejected. However, I did tell him to go buy a box of factory ammo to see if that makes any difference, to at least try to eliminate a variable.

[Brian Pfleuger]

You suggest "GAP" in your title but then say that your father fired your 45ACP loads?

I'm fairly certain that you could either not fire a 45ACP in a GAP chambered gun or if you managed it then you would blow up the gun because it would be radically out of battery. So, I assume that your fathers gun is actually a 45ACP and you refer to it as a GAP simply because it's a Glock? 'Cuz if yours is an ACP and your father's is a GAP then there's your problem.


If both guns are, in fact, 45ACP then you'll have to describe the type of jam that you're experiencing and let us know what the load is that you are using. (Powder, charge, COAL, bullet...)

[Tuzo]

Bad idea to force 45 ACP into a Glock 45 GAP. One major difference is the case length: .896" ACP and .760" GAP. Rim diameter is also different: .480" ACP and .470" GAP.

[Skewed]

It was jamming when it was chambering a new round. The slide was not sliding all the way forward. It looked very similar to if the crimp was not tight enough and does not allow the round to fully seat in the chamber, thus holding the slide back.

I was using rounds that I reloaded to use in my 1911 into his Glock. At the moment when I gave them to him it did not seem like such a bad idea. Since I do not particularly see any .45 factory ammo designated specifically as GAP. I know it exists, but I was thinking it was for marketing purposes.

[Brian Pfleuger]

Since I do not particularly see any .45 factory ammo designated specifically as GAP. I know it exists, but I was thinking it was for marketing purposes.

What model is your fathers Glock? There are Glock models chambered in 45ACP and 45GAP.

45ACP and 45GAP are different cartridges with different length cases and different COALs. Forcing a longer ACP cartridge into the GAP chamber could be potentially catastrophic.

It sounds like that's exactly what you were doing though.... the 45acp round would not chamber properly in the GAP gun because 45ACP is almost a 1/4 inch longer than a GAP round should be.

[Unclenick]

The OP may have not realized .45 GAP is a different cartridge? The GAP is a shorter round. As stated, .45 ACP should not be chambered in a pistol chambered for .45 GAP. It shouldn't even fit in unless the .45 were taper crimped into lead bullets down to the point the case mouth went into the throat. That would tend to raise pressure dangerously and be hard to extract and eject.

[Skewed]

The OP may have not realized .45 GAP is a different cartridge? The GAP is a shorter round.

That is certainly appearing to be the case. As I said though, the rounds did work, but not as well as they do in my gun. Visually though, they appear to fit fine with the exceptions of two or three rounds that got hung up.

[SL1]

The OP wrote:

For the most part they did fine but he jammed a few times.

and

I have also noticed that his gun will sometimes not fire the round either. When this happens there appears to be a more than significant impact dent on the primer but it does not set it off. Giving it another try will set it off, I even took one and put it in my gun and tried it and it fired the first time, but with two dents in the primer when ejected.

So, it sure READS like he was firing his ACP rounds in his father's gun. If his father's gun IS chambered for the GAP cartridge instead of the ACP cartridge, he was REALLY lucky with this outcome.

SL1

[Skewed]

So, it sure READS like he was firing his ACP rounds in his father's gun. If his father's gun IS chambered for the GAP cartridge instead of the ACP cartridge, he was REALLY lucky with this outcome.

Yes, I was using my ACP rounds in his Glock. I am finding out which Glock his actually is. Damn, this scares me.

But now it opens a whole new set of problems. When I pick up range brass, I just wonder how many GAP casings I have been picking up thinking I am getting ACP and not realizing it.

Time to start beating myself up. I do not usually screw things up like that.

[Unclenick]

Yup. That's apparently what happened. His handloads just appeared to be low enough in pressure that they didn't blow the cases open. Very lucky. I had that happen once. Destroyed the grip panels, magazine and remaining rounds, and blew brass particles back into my face (glad I always wear glasses).

[Skewed]

I suppose the saving grace is the fact that I am using 4.9 grains to load the acp.

[jeffreybehr]

"I suppose the saving grace is the fact that I am using 4.9 grains to load the acp."

That info is meaningless unless you tell us which powder it is.

[David Wile]

Hey folks,

It is somewhat embarrassing to have to admit my lack of knowledge of the many Glock pistols. I am fairly familiar with the .45 ACP cartridge and some of the many pistols chambered for it, however, I also have to admit that I have never heard of the .45 GAP cartridge.

From what I have read on this thread so far, it would seem there is a .45 GAP cartridge in addition to the old traditional .45 ACP cartridge, and there is no reason for anyone to assume they are interchangeable. Most pistols today are usually clearly marked with the cartridge it shoots on the chamber part of the barrel where it can be easily seen through the eject port. I would assume that a .45 GAP Glock pistol would also be clearly marked as to what cartridge it was designed to shoot.

This is pretty basic shooting information, and if the original poster is not aware of this basic information, I would think such a person should go back to square one and start with a basic shooting class targeted toward all firearms including rifle, shotgun, and pistol. This sort of thing is addressed at the Boy Scout level of firearms training and initial hunting courses in most states.

It is not my intention to be unkind by humiliating the original poster, but he and his dad really need to step back to learn the basics before going out to the shooting range. I know cartridge names can sometimes be confusing, but you really need to learn what is necessary to clear up the confusion before shooting something that is "confusing" to you.

One example of confusing is the 9MM cartridge. When you say 9MM, do you mean 9MM Luger, 9MM Parabellum, 9MM Corto, or 9MM Makarov? The 9MM Luger and Parabellum are the same cartridge and are indeed interchangeable. However, the 9MM Makarov is a different cartridge and can not be interchanged with the 9MM Luger/Parabellum.

Some firearms may not be clearly marked as to what cartridge they were intended to shoot. If that is the case, then a knowledgeable shooter would do whatever is necessary to positively identify the firearm and what ammunition is intended to be used in it.

It sounds to me like the original poster and his dad were lucky the Glock did not go to pieces.

Best wishes,
Dave Wile

[Scorch]

45ACP ammo will not chamber in a pistol chambered for 45GAP, there is a 1/8" length difference. The issue is somewhere else, probably seating depth.

[Brian Pfleuger]

Originally Posted by David Wile

Most pistols today are usually clearly marked with the cartridge it shoots on the chamber part of the barrel where it can be easily seen through the eject port. I would assume that a .45 GAP Glock pistol would also be clearly marked as to what cartridge it was designed to shoot.

The Glock pistols are indeed so marked.... but the difference is relatively subtle.

The 45ACP version is marked ".45 Auto"

The 45GAP version is marked ".45 G.A.P."

In addition, the GAP is a relatively unknown cartridge. I can easily see the potential for confusion.

[Unclenick]

Scorch,

No. The OP clarified that he couldn't get the Glock slide to close completely, so he was firing partly out of battery. Allow that the Glock chamber, like most .45 ACP chambers, are cut a little generously, and that's what would happen putting an ACP into the GAP chamber.

[Skewed]

Scorch,

No. The OP clarified that he couldn't get the Glock slide to close completely, so he was firing partly out of battery. Allow that the Glock chamber, like most .45 ACP chambers, are cut a little generously, and that's what would happen putting an ACP into the GAP chamber.

I willingly admit that I may have made a mistake and I will take any and all corrective measures to see that this does not happen again. But the glock was indeed handling the acp rounds fairly well, out of 50 rounds 3 jammed. While that number is still undesirable, I at least noticed there was a problem there to pose the question. I am using 230gr round nose, with 231 powder at 4.9 grains.

[Tex S]

When I pick up range brass, I just wonder how many GAP casings I have been picking up thinking I am getting ACP and not realizing it.

I'm sure the GAP cases would be marked accordingly.

[Skewed]

I'm sure the GAP cases would be marked accordingly.

I would have thought so too. And I will certainly be paying closer attention from here on out.

The one thing I did notice a while back on some cases I picked up. The primer was small. My press would punch it out but would not seat a new one. Upon closer inspection, besides the smaller primer, the pocket seemed to have had a sleeve that was there to take up the extra space that the smaller primer would have left. These headstamps were marked with "WIN - NT". I ended up just tossing those out.

Dammit Glock, why did you have to go and re-invent the wheel?

[Scorch]

The one thing I did notice a while back on some cases I picked up. The primer was small. My press would punch it out but would not seat a new one. Upon closer inspection, besides the smaller primer, the pocket seemed to have had a sleeve that was there to take up the extra space that the smaller primer would have left. These headstamps were marked with "WIN - NT". I ended up just tossing those out.

Those are not 45 GAP ammo, they are Winchester 45 ACP non-toxic primed ammo. If you had looked at the flash hole, you would have also noted that it is much larger than the flash ole in a regular 45ACP case. And the primer pocket is not sleeved, it is crimped.

The OP clarified that he couldn't get the Glock slide to close completely, so he was firing partly out of battery.

I'm sorry unclenick, but I disagree. That would be significantly out of battery, and the disconnector would prevent it. If it were to fire it would be catastrophic.

[spacecoast]

Hmmm.... a little like forcing a .357 into a .38 chamber, right? All the possible outcomes are BAD.

Did the ACP ammo fit in the GAP magazine?

[Tex S]

Those are not 45 GAP ammo, they are Winchester 45 ACP non-toxic primed ammo.

I hate those damn things. I just throw them away.

[Unclenick]

Originally Posted by Scorch

I'm sorry unclenick, but I disagree. That would be significantly out of battery, and the disconnector would prevent it. If it were to fire it would be catastrophic.

Agree that it shouldn't work, but I've seen 1911's that would accept a case 0.050" too long in full battery just because the back of the barrel extension to breech face fit had a lot of slop. Should never happen, but has. If the Glock had that kind of tolerance, the failure to chamber might mean only 80 thousandths or so protrusion out the back. Enough to let some 1911 disconnectors rise, I know. Glocks are less familiar to me, having shot them but never worked on one, so I fully admit ignorance of how tightly their disconnectors normally operate?

In any case, there is nothing to be gained arguing about a fact. It'll either be so or it won't. I'm hoping the OP will get back to us after asking his Dad to get a model number or read the chambering stamp on the barrel at the ejection port (if that gun has one)? It suppose it could also be a .45 ACP Glock with a tight chamber that doesn't let the OP's loads all the way in? Seating either too deeply for the bullet or a little too far out for the chamber can cause that, too.

[Ridge_Runner_5]

Since I do not particularly see any .45 factory ammo designated specifically as GAP.

You mean like these?

[Skewed]

Did the ACP ammo fit in the GAP magazine?

Yes, visually everything looked ok and loaded ok. Nothing had to be forced in anyway, everything slid right into place with out any resistance, other than the 3 rounds that jammed.