45 ACP with small primers?


March 8, 2011, 02:22 AM
So I just got done packaging about 7k rounds to sell on the boards. After counting out 5k i noticed about 8-10% were small primers. So I went back and separated them and recounted them. My questions are:

1) Why would they make 2 different primer setups with the same cartridge?
2) Does anyone reload these and if so do you want them? Make me an offer. I would say I at least have 400 of these.


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March 8, 2011, 04:28 AM
I was thinking the same thing. I picked up a box of Blazer alum cased .45's the other day to see how they would run & they were small primers. My Federals are large. I have no idea whythey are like that. Maybe someone can chime in on it?

March 8, 2011, 04:46 AM
I read something about that a few months ago. If I remember it right, the small primered ones still worked fine. It had something to do with primer availability. 45 brass isn't too hard to find, if you don't want it, either give it to someone who does or use it yourself if you have some small primers laying around.

March 8, 2011, 05:47 AM
I first discovered them a couple of years ago. I bought 50 rounds at a gun show to try a new 1911. I picked up the brass and threw it in with my other .45 cases. I didn't learn about the small primer stuff until it jammed up my reloading process. I threw those out........A couple of weeks ago, I got 1k pieces of brass off someone on another board. I did not ask whether it had small primers or not. About 10% did. I did not throw them out. I figure when I get a big enough pile of them, I load up a batch.

March 8, 2011, 07:08 AM
I learned of their existence about 8 years ago. It was a box of Winchester Win Clean 45 ammo. It was cheap but unreliable with truncated cone bullets. THey might still make it but I dont shoot 45 anymore. The reloads I made were better than the factory by far.

It may have been standard to have the small primer pockets or they may just have done it to save a little money.

March 8, 2011, 07:25 AM
PM 918v. He was looking for SPP .45. He might be interested.

March 8, 2011, 10:45 AM
It has nothing to do with primer availability.
SM primed .45 ACP is from NT, kleen-range" or "lead free" primed ammo.

The lead-free Dinol primers have a much more vigorous explosion then normal primers, and early lead-free ammo was causing gun damage. What happened was, the primer fires, backs out of the cases, and eventually peens a dent in the breach face.

Three things were done to prevent the gun damage early on.
1. A larger flash hole decreased the primer pocket pressure considerably which reduced the violent backing out to more normal levels.
2. Primers were crimped in place to help prevent them backing out.
3. A switch to Small primers in calibers that had traditionally used only large primers was made.

Now, the lead-free primer issue has been addressed by further refinement of the Dinol priming mix.
The crimped in place primer is pretty much gone.

But the large flash hole & Sm primer is still being used.

They can be reloaded normally with no difference in pressure or velocity.


March 8, 2011, 11:21 AM
Here we go again! The search function will turn up about a dozen threads on this subject, but I'll once again give a short tutorial on the use of small pistol primers in the .45 acp.

The use of small pistol primers in .45 started (at least in this country) when the quest for primers without lead styphnate started several years ago. This was prompted by the increased use of indoor ranges and people concerned with lead poisoning. The quest is ongoing, by the way, and I was told by a technician at the ATK booth at the SHOT Show in Las Vegas in January that it wouldn't be long before all primers would be Non-Toxic, and not contain lead.

Anyway, the Non-Toxic (NT) priming compound, which is an explosive, just like lead styphnate, has a higher brisance than the lead styphnate compound. Brisance is the velocity of the explosive gases. The increased brisance made the primers back out of the primer pocket faster than lead styphnate primers, so they would expand outside the primer pocket before the burning powder inside the case had a chance to produce enough pressure to push the case back and reseat the primer. (this is what occurs when a cartridge is fired) This caused excessive flattening of primers and the brass primer cup would flow.

The first attempt to fix this problem was enlarging the flash hole to almost 1/8" in diameter. This was done by both Federal and Winchester. These cases will load just fine, by the way.

The second attempt at a fix was to add a heavy crimp to the primer pocket, after the primers were seated. This is similar to what's done on military ammunition intended for use in full automatic firearms, which keeps a primer from exiting the primer pocket and jamming up the works, usually at the worst possible time.

Neither of these fixes proved fully satisfactory, so the next iteration was the use of the small pistol primer. The volume of the .45 acp case doesn't really require a large primer anyway, but "we've always done it that way". The small pistol primers work just fine, and some reloaders have reported increased accuracy when using the small pistol primed cases.

The Bushmaster reported he got about 50 fps less velocity when he conducted some tests on the two different primer size cases, but no loss in accuracy. I've also found no loss in accuracy, but haven't bothered to run them across the chronograph to measure any possible velocity differences, since they all hit at the same point on target.

I've seen small pistol primed .45 acp brass from Winchester, Federal and Speer. It's not going away, so you might just as well sort it out and reload it. Repeat as necessary.

Hope this helps.


March 8, 2011, 11:23 AM
RC and I were typing at the same time, but I went to get a second cup of coffee in the middle of my reply. Must be the time difference between middle America and the Coast.....


March 8, 2011, 11:24 AM
I found a general increase in accuracy with these small primer cases.

smurf hunter
March 8, 2011, 11:58 AM
It seems logistically desirable to use the small primers, since they are vastly more common for pistol ammo.

March 8, 2011, 12:24 PM
How much do you want for them?

March 9, 2011, 02:43 AM
Glock switched to SPP when they made the GAP round. Their stated reason was that the SPP was good enough, and it reduced the possibility of the ejector hitting a primer in the process of hand-ejecting a live round from a pistol.

If it's good enough, then the question is why is .45 brass still being made with LPP? Small pockets are less prone to stretching and becoming loose. There's no upside for LPP, other than tradition.

March 9, 2011, 11:09 AM
Post #8, "We've always done it that way".

The same reasoning was used for the .40 S&W in 1991, when Winchester brought it out. The small pistol primer was enough primer and the ejector wouldn't hit it. The 10mm parent cartridge uses the large pistol primer, but could have probably been made just as well with the small pistol primer.

Hope this helps.


March 18, 2011, 11:25 PM
If anyone has enough .45 ACP brass cases with small boxer primers to make it worth mailing, I'm interested in buying them. I use 'em in my 1911 in .400 Corbon.

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