Primer Size Changeing Load


November 18, 2010, 09:14 AM
If most cartridge (45 acp) normally took a large primer but the odd one actually took a small pistol primer would that change the load specs?

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November 18, 2010, 10:30 AM
Short answer yes. But how much???

I have been reading about these "New" .45 ACP's with small pistol primers in them and all I can say is what the heck are they thinking!

Just so you know I did read that on the box of Winchester Winclean .45 ACP it says not to reload this brass? I can't remember where I read it but, I would research this before continuing reloading that brass.

November 18, 2010, 11:31 AM
Lead free ammo is using sm primers due to the nature of the Dinol lead-free priming compound.
It produces a more vigorous pop then regular priming compound.

Early lead-free ammo was using Lg Dinol Primers, and damage was occurring (peening) to the breach face of certain handguns from them blowing out of the case so violently.

Three things were eventually done to cure the problem.
1. Switch to Sm Lead-Free primers that hold less compound.
2. Larger 1/8" flash holes in the case to reduce primer pocket pressure.
3. Crimping the primers in place in the case like GI ammo.

You can load the Sm Primer .45 ACP using your normal load data.
Apparently, the larger flash hole makes up for the weaker primer.

But my advice is, if you only have a few, toss them.
They are a real PITA when mixed with regular Lg primer cases.
Especially if they have crimped-in primers that have to be reamed or swaged before a new primer can be inserted.
And even more especially when using automated priming systems on progressive presses.


November 18, 2010, 12:49 PM
I, and several others on this board, have been loading the small primed .45 acp brass ever since it appeared on the scene. There have been no problems in loading it, other than the difference in the primer size. The Bushmaster noted an approximate 50 fps velocity drop in his loads with the small pistol primer, but that's probably dependant on the powder used and the charge of that powder. (and the way he holds his mouth when he shoots)

The bottom line is, they load and shoot just fine.

Hope this helps.


November 18, 2010, 01:03 PM
I got about 1000 of the small primer brass in a large lot that I came across and just had to buy. I've been using them to dispose of the excess of SP magnum primers that I have. They all feel the same to me.

November 19, 2010, 12:32 AM
It sure is good to know that some of you have not had any issues!:cool:

I not having a .45 ACP and don't load for it never even thought to look for the smaller primers. I just started selling once fired pistol brass and it has now added a ton of work to my sorting job! :fire::cuss::banghead:

November 19, 2010, 11:24 AM
Thanks for all the input. RC I loved all the detail in your answer.

GW Staar
November 19, 2010, 01:35 PM
A friend of mine who uses a Lee Pro 1000 for just .45s, asked me to come over a few nights ago, and help figure out what he was doing wrong.

Upon examining the situation, he was crushing primers one right after the other. Took me a few minutes, but I discovered the culprit was some range brass he picked up...a whole box of 50 once shot Speer cases. :) Yup, small primer holes, and many crushed large primers. He was real lucky he didn't get a kaboom surprise.

Just telling the experience to let people know, who use progressives, that big primers don't go in small holes.:D One more thing to complicate our lives, now we have to sort .45's by primer size.

November 20, 2010, 07:55 AM
I sort and inspect all my brass after size/deprime step. All the small primer 45 ACP goes into a seperate container. I reload these with a worked up load that is for my MAC 10 for use where I probably will not bother to get my brass back. No big loss there.:D

December 23, 2010, 01:01 PM
I bought some federal .45 ACP about 2 weeks ago. That was the first time I seen the small primer type. My question is why change it? Just the appearance after knowing the norm is L Primers, even though it MAY (or may not) have the same specs is just questionable!

December 23, 2010, 01:24 PM
My question is why change it?
Please read Post #3.
Or, read post #3 again.

I don't know how to explain it to you any further then that.


December 23, 2010, 02:49 PM
Unfortunately, some pholks, (and companies) just love change for the sake of change, even if the end result is worse. :banghead::banghead:
(maybe voters too??):p

December 23, 2010, 05:33 PM
The change to Non-Toxic primers was the result of demands from the consumers, particularly those who only get to shoot on indoor ranges. Some indoor ranges were built many years ago, with inadaquate ventilation, and there were some serious cases of high lead levels in the blood of both shooters and employees. There were also large police departments and the military who demanded it. It was determined that the source of the high lead levels was two fold, the lead styphnate in primers, and the exposed lead at the base of the bullets.

This resulted in more common use of plated bullets, with no lead exposed, and lead free primers. As has been explained many times on this board, and others, the transition to lead free primers wasn't without it's difficulties. It went through several attempts to come up with a combination that worked, and the small pistol primer was the answer in the .45 acp, which really never required a large primer in the first place, since the volume of the case is relatively small and it's a low pressure round. In 1905, when John Browning invented the .45 acp for his new pistol, large primers were used in large cases, period.

The small pistol primers weren't used in .45 acp to screw anyone over, or to make life difficult for reloaders. It was done out of necessity. It was harder for the manufacturers to retool their brass making, and loading lines, than it is for reloaders to sort through their brass for the occasional small pistol primed case. It was also much more expensive for them.

If it weren't for the internet, most shooters would just either ignore them, or use them, without a bunch of complaining to other anonymous shooters..........

Hope this helps.


December 23, 2010, 07:15 PM
I haven't seen a small primer .45 ACP case yet, but I shoot at an outdoor range, so maybe that's why.

Fred explained it. Manufacturers do not go through the expense of changing things without very good reasons.

If I do run into some small primer .45's, I'll just start tossing them in a bucket by themselves for later use.

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