I am new to reloading, and it seems to be a very short supply of 45 acp bulk brass, and after looking at several sights I have seen that thee 45 gap seems to be more available and rated for higher pressure to boot only marginally shorter. What do you think, and do you know what the effective minimum COAL length is for 45 acp? I have seen max #'s, but no minimums. If it helps, I am reloading for a Kimber ultra compact 3"

The OAL I've always used for 45 ACP is 1.230.

I've never heard of anyone loading 45 GAP to shoot in a 45 ACP.

I don't even know it a 45 GAP will chamber in a gun chambered for 45 ACP.

I do some research and come back.

Hack

thanks for taking a look, i look forward to hearing back from you on your results

Okay, I'm back. Most of the things I found were just comparing 45GAP to 45ACP, but I did find one that said , no, do not shoot a 45 GAP in a gun chambered for 45 ACP.

Here's the source that said no to shooting GAP in ACP platform.
http://wiki.answers.com/Q/Is_i...a_gun_made_for_45acp

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I would not shoot a 45 GAP in my Springfield 1911 A1 (chambered for 45 ACP)

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I also found out that the OAL of a 45 GAP is 1/10 less than a 45 ACP (the source said 1.130, which is 1/10 less than the 45 ACP's 1.230).

The range of OAL for the 45 ACP was given to be 1.200 to 1.250, but like I said, I only use 1.230.

The source for the above info is:
http://www.thefiringline.com/f...ex.php?t-190780.html

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Hack

can anyone give some input to this, it seems to say that headspace is irrelevant on a 45 acp

Now let's add a complication in the form of the extractor. If the extractor wasn't there every case would go into the chamber until it hit bottom and it really would headspace on the case mouth. Of course it might not go bang then either. Given the variables in cases and chambers there might not be enough firing pin protrusion to hit the primer.

So how the heck does the good-old .45 manage to go bang so reliably? It's simply because it has a good extractor. When the round is stripped from the magazine it slides under the extractor hook and is held against the breech face. Unless the slop between the rim thickness and the width of the cut in the extractor is greater than the firing pin protrusion, the gun can't help but go bang. Imagine that. Ain't conventional wisdom grand?

Yes it headspeaces off the case mouth and yes if the extractor was not there it would not go bang all the time so it should read the 45 acp was designed to headspace off the case mouth but in reality it headspaces of the rim.

And because of this don't shoot 45 gap in a ACP pistol.

quote:

Originally posted by Kimber09:
can anyone give some input to this, it seems to say that headspace is irrelevant on a 45 acp

Now let's add a complication in the form of the extractor. If the extractor wasn't there every case would go into the chamber until it hit bottom and it really would headspace on the case mouth. Of course it might not go bang then either. Given the variables in cases and chambers there might not be enough firing pin protrusion to hit the primer.

So how the heck does the good-old .45 manage to go bang so reliably? It's simply because it has a good extractor. When the round is stripped from the magazine it slides under the extractor hook and is held against the breech face. Unless the slop between the rim thickness and the width of the cut in the extractor is greater than the firing pin protrusion, the gun can't help but go bang. Imagine that. Ain't conventional wisdom grand?

quote:

Originally posted by kcstott:
Yes it headspeaces off the case mouth and yes if the extractor was not there it would not go bang all the time so it should read the 45 acp was designed to headspace off the case mouth but in reality it headspaces of the rim.

And because of this don't shoot 45 gap in a ACP pistol.

Partially right and partially wrong.

To prove it to yourself, strip the barrel out of your .45 ACP chambered pistol. Insert a loaded cartridge (use a factory loaded round, please. It is bound to be properly taper crimped. A roll crimp will not headspace properly.) It headspaces on the case mouth. No extractor holding the rim. What stops the cartridge at that exact place? That shoulder which is 0.898" into the chamber.

Reassemble the pistol without the extractor and feed a primed, empty 45 ACP case into the chamber. Pull the trigger. (wear earplugs and beware of the minor amount of flame it will produce. It will powder-burn and stain cloth, burn skin and pepper you with debris. Don't ask me how I know.) Did the primer go bang? I'll bet, "yes". Certainly the extractor could not be what provided the headspacing, since it is still on your workbench.

Insert a .45 GAP cartridge in the (disassembled) .45 ACP barrel's chamber. Drops furthur in, right? (0.898-0.755 = 0.143") Try to fire a primed, empty 45 GAP case without the extractor in place or with the cartridge deliberatly NOT engaged with the cartridge rim. (That is, no fair pressing the cartridge up against the breechface prior to firing.)

Partially right: If the cartridge is held against the breechface well enough, the firing pin will set off the primer. After that, pressure holds the cartridge walls against the chamber and the extractor works like it should. Where the problems arise is if the extractor does not go over the rim, but simply pushes the cartridge ahead of the extractor nose, deep into the chamber. Instant jam, failure to extract when you do the clearance drill and extreme embarrassment.

Partially wrong: You cannot count on the extractor to engage and to hold that case rim every time. Not in competitive shooting and certainly not in a gunfight.

quote:

Originally posted by btefft:
I also found out that the OAL of a 45 GAP is 1/10 less than a 45 ACP (the source said 1.130, which is 1/10 less than the 45 ACP's 1.230).

The range of OAL for the 45 ACP was given to be 1.200 to 1.250, but like I said, I only use 1.230.

Note that since we are headspacing on the case mouth, the length of the overall cartridge is irrelevant. It is the distance from the case mouth to the base, which in the .45 ACP is .898 and in the .45 GAP is 0.755. Where the nose of the bullet winds up is only of importance to the cartridge fitting in the magazine and running up the feed ramp.


Please pardon my being blunt. It is late.

Lost Sheep

Blunt is good for getting the point across.

Well, written treatise.

As you could probably see I was grasping for straws. I guess my final conclusion was okay, don't shoot a 45 GAP in a 45 ACP platform, right?

Thanks

Hack

Well just did a quick look. www.grafs.com has several brands of 45ACP brass in stock. Also Starlinebrass shows 45auto available.

quote:

Originally posted by Kimber09:
can anyone give some input to this, it seems to say that headspace is irrelevant on a 45 acp

Now let's add a complication in the form of the extractor. If the extractor wasn't there every case would go into the chamber until it hit bottom and it really would headspace on the case mouth. Of course it might not go bang then either. Given the variables in cases and chambers there might not be enough firing pin protrusion to hit the primer.

So how the heck does the good-old .45 manage to go bang so reliably? It's simply because it has a good extractor. When the round is stripped from the magazine it slides under the extractor hook and is held against the breech face. Unless the slop between the rim thickness and the width of the cut in the extractor is greater than the firing pin protrusion, the gun can't help but go bang. Imagine that. Ain't conventional wisdom grand?

No, headspace is not irrelevant. The 45acp headspaces on the mouth. You can NOT use 45gap brass w/ any reliability. Just buy 45acp brass & move on.

thanks to the input, and the links for the information and to get some 45 acp brass

kimber09

Just another note...

About two weeks ago I was loading a bunch of 45 ACP ammo with some range brass we had picked up over time. Unbeknownst to me, a few 45gap cases had made their way into the lot. The primer hole on the 45gap cases is too small to accept the primers I was using.

Just an observation...

I just picked up 2000 .45 ACP from dominion.

www.dominionshootingrange.com

brassmanbrass.com or l.e.o.brass are the least expensive I've seen so far.
John