I have found a stockpile of sm pistol mag primers and I was wondering if they can be used in 9mm. I primarily load cast bullets with red dot. Can this be done safely?

thanx,
mark

if you aren't super high pressure with std primers, then yes

Ditto what Jeffe said; maybe drop your charge a little the first batch to be sure you aren't at +P already.

If I work up an overload with 9mm to loose primer pocket, it takes ~ 65% extra powder.

Contrast with the 270 that takes 5% extra powder to get the same loose primer pocket.


Knowing where that threshold is in 9mm, the powder can be reduced, switch to a magnum primer, and worked up again.

The new threshold of brass failure will be ~ 0.7 gr less powder than with standard primers.

The velocity at threshold with magnum primer will be less than the velocity with standard primers.

So instead of 5 gr extra powder, I can only use 4.3 gr extra powder.

Few powders have the density - speed product to case harm to the brass in 9mm.

You cannot fit enough Bullseye in a 9mm case, with any bullet, to hurt the brass. Most people do not know that.

Powders that can cause over pressure in 9mm are, but not limited to; AA#5, HS6, and 3N37.

AA#5 is so fast and dense, it can be overloaded with light bullets.