Firing .45 GAP from a .45 ACP revolver

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stevieboy

New member
Has anyone fired .45 GAP ammunition from a revolver that is chambered for .45 ACP? I've never thought to do it with my Smith & Wesson 625 but, logically, it ought to be possible. As I understand it the only difference between the GAP and the ACP round is casing length. Diameters are the same, yes? And the GAP should fit into moonclips that are designed for .45 ACPs, shouldn't they?

So, can it be done? And, the follow up question is: should one do it? Are pressures significantly different between the GAP and ACP rounds? Is there a risk of damaging chambers or barrels firing GAP from a .45 ACP revolver? And, finally, how about accuracy?
 
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Lavid2002

New member
It wont headspace properly...

Possible FTF

Also has higher pressures if im not mistaken *Im pretty sure it does*

Dont do it

Edit: Missed the revolver part : )
 
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Locoweed

New member
Of course it will work. Headspace is okay because in moon clips they are headspacing on the clip, not the rim or the case mouth. A .45 acp will normally headpsace on the case mouth without a moon clip but a GAP would be too short thus would require the clip. In .45 Auto Rim the cartridge headspaces off the rim. I can't imagine why the GAP wouldn't work just fine in a 625 with moon clips. I've got a 25 and a 625 and will be more than happy to test the theory if someone will send me some GAP ammo.
 
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bigghoss

New member
it'll work just fine with moon clips. but won't work without them due to headspace. just like shooting .40 S&W in a 10mm
 
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Lavid2002

New member
Just note that 45 GAP pressures are higher than 45 ACP

Saami Specs
.45 GAP 23,000 PSI
.45 ACP 21,000 PSI

Not that big of a difference....but should be noted
 
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MrBorland

New member
As I understand it the only difference between the GAP and the ACP round is casing length.
Click to expand...

GAP uses small pistol primers as well (I recall the brass may be a teensy bit thicker at the base too). I just bought a 625 and thought about loading 45GAP because i have a bunch of small pistol primers already on hand. I decided that was a silly reason to ditch the tried and true .45ACP, so I bought some large pistol primers and never ended up loading .45GAPs

And the GAP should fit into moonclips that are designed for .45 ACPs, shouldn't they? So, can it be done? And, the follow up question is: should one do it? Are pressures significantly different between the GAP and ACP rounds? Is there a risk of damaging chambers or barrels firing GAP from a .45 ACP revolver? And, finally, how about accuracy?
Click to expand...

Theoretically, GAP ought to fit ACP moonclips. The guys over on the revolver forum of BrianEnos.com have been messing with this for a while. Yes, it can be done, but some GAP brass seems to fit loosely, while others haven't had any problems. Hearthco makes GAP-specific moonclips.

AFAIK, the jury's still out on whether the shorter case speeds reloads. That the best competitive wheelgunners haven't come to a consensus suggests to me there's no clear speed advantage. I suspect one would have to be shooting at the GM level for it to matter.

Also AFAIK, 45GAP pressure's a little higher than 45ACP, but not much. Not enough to damage the gun.

I don't know that you'd lose (or gain) accuracy.

Try it and let us know how it works.

http://www.brianenos.com/forums/ind...&do=quick_search&search_app=core&fromsearch=1
 
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EdInk

New member
Jerry Miculek uses .45acp in moon clips. I think if it could save 1/10th of second he would be doing it. I think the longer case adds a tiny bit if weight which helps the cases fall/extract (with a full length extractor) easier. I know this happens with regular rimmed cartridges, especially in SAA style revolvers. I can empty and reload .357 quicker than .38 in my vaquero because the heavier 357 brass falls out with gravity and the 38 usually has to be pushed with the rod. YMMV.
 
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Webleymkv

New member
The pressures (23,000 PSI) is right in there with the .45 ACP +P. I would also think it would work.
Click to expand...

You are correct sir. .45 ACP +P pressures should not be an issue in a 625 (many people shoot .45 Super ammunition in them), so as long as the moonclips hold the cartridges properly, you shouldn't have an issue.

The real question is why you want to do this? .45 GAP ammo is typically no more available nor less expensive than .45 ACP, the minute difference in case length is unlikely to make any meaningful difference in reload time, and .45 ACP +P ammo offers superior ballistics to the GAP round.
 
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zzclancy

New member
Because I have a lot of 45 gap ammo

I have a lot of 45 GAP ammo for a Glock that is totally unreliable. It's been to gunsmith's and a police armor.

So I picked up a JM 625 today and it hit me. Could I use the 45 GAP ammo as cheap practice ammo. A little higher pressure. Case is shorter. Full moon clips I'm going to give it a try in a few weeks.

If anyone knows of a good reason why I shouldn't please post. I bought it for the 45 acp. But I don't like the Flock, never liked them. Wife has two in 40 S&W. Never had a problem.
 
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44 AMP

Staff
Congratulations!!!!!

In at least the last decade, you are the first person I've found who admits (without coaxing) that such a thing as a un-reliable GLock could even exist!!!!

Firing the GAP ammo from a DA revolver with clips ought to work just fine. In fact, it is the only way to fire the stuff, unless you have a GAP chambered barrel. Won't work in a SA revolver.

Now, just to be clear you got the S&W and now are wondering about firing the GAP ammo from it. You didn't get the S&W just to fire the GAP ammo, right?

:rolleyes:
 
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James K

Member In Memoriam
Just note that any time a cartridge is supported against the firing pin blow on a "moon clip" the spring of the clip serves to cushion the firing pin blow to some extent. In some cases, that might result in misfires but it is more likely to result in inaccuracy due to the differing primer ignition.

Jim
 
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stubbicatt

New member
James K, while the theory is sound, I haven't found my 45 ACP revolver to be inaccurate with clips. Or if it is, it would take a seriously much better shot than myself to determine this.
 
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Lunkhead

New member
I can vouch for James K's theory. I routinely get misfires in my S&W 610 using .40 in moon clips. Every time it is a light primer strike that I have narrowed down to the energy absorption by the moon clip. Not one single instance using 10mm that headspaces on the case mouth.
 
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Don P

New member
As stated by many posts the difference in case length is acp is .898" and the gap is .760", difference of .138" a touch over 1/8". Many of the 627 shooters use 38 short colt brass over 38 spl. The short colt loads are much faster to reload in moon clips because of the greatly reduced wobble of the rounds in the clip. I agree if JM could gains a few 100 ths. of second on a reload using gap ammo he would have done so.
 
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James K

Member In Memoriam
Hi, Stubbicatt,

Unless your .45 ACP revolver is unusual, the cartridge is NOT supported by the moon clip, but by the mouth of the case butting on a shoulder in the chamber. Only a few of the first Colt M1917's did not have a chamber shoulder; all the S&W's did and all the subsequent guns do.

Jim
 
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Lunkhead

New member
I used the plastic ones. I borrowed a single metal type, and had no misfires in a short trial through a few cylinders. I guess I should have mentioned that tidbit.
 
4

44 AMP

Staff
I'd say the plastic is most likely your problem. When firing a shorter case (rimless) in a DA revolver, the only thing actually holding it in place is the clip.

Any plastic that has the plasticity to not be to brittle to use will have some cushioning effect.

ALSO, the fit of the clip in the gun will matter. Probably not so much with new commercial guns (I have no experience with the 10mm), but I do have a 1917 Webley Mk VI, converted to use .45acp BRASS.

In it, I have ONE brand of half moon clips that work flawlessly. ALL the full moon clips I have found will not work in the gun, they are too thick.
 
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