I am not a pistol reloading guru. I have a question, what is the reason for 45 acp brass being made with small primer pockets and large primer pockets? Any advantage of one over the other?

From what I understand, the small pistol primer brass was for the eco primers for indoor shooting. The small primers were more indoor safe with less toxins. It's also a reloaders nightmare with the small and large primed brass! The 45 ammo I sell is small primer brass.

The original 45 ACP brass was 30-06 brass cut down, which has a large primer pocket. The large primer pocket is not needed, but what was used for the brass.

Thank You, Sir

Well that's a cool piece of history. I did not know that.

Couple of technical points on small vs large primers in 45 ACP. With identical powder charges, a large primer will produce more velocity than a small, especially with slower powders. With the faster powders, large primers will produce higher pressures. So work up loads with either small or large primers and stay with only that one.


https://www.starlinebrass.com/articles/Small-Primer-vs-Large-Primer/

Now, I am as smart as Chad, JG, and JeffBird!!!!!! ALMOST!

I like the small primer brass, because I can buy one size of primers and load 9mm, 38 Special, .357 Magnum and .40 S&W with the .45 ACP. Otherwise, I have to buy two primer sizes and swap the priming system on my press. So I see it as an advantage.