I picked up a bunch the other day at the range. I went to put primers in them and some (Federal) had small pistol primer holes and the others (Sig) had large pistol primer holes. They both were labeled "45 Auto".
What's up with that?
As I understand it, it is mainly due to "green" ammo. The lead free primers are only made in small, so they changed to small primers in .45, which is the only major pistol round that they wanted to do "green" and used a large primer.
New stuff, you are correct. But historically a lot of “match” 45 acp ammo was manufactured with small primers. There are guys who go out of their way to find small primer 45 brass.
I got a great deal on a Dillon 550 so one set for large primers and the other for small ones. When I need to load some small premiered brass I just switch the head to the other machine. Done in seconds
I already had one