[mrerick]

"So we still don't know if its a 30 Cal are a 9mm. Okay what do I need to do to find out what caliber is. What other information do y'all need on this Luger "

Just look at the post I linked to earlier... It's clearly photographed.

A 9mm Luger cartridge will not fit all the way into a .30 Luger chamber, even though the rim is the same size. This is because the .30 Luger cartridge is a bottleneck cartridge with a bevel bottleneck case.

Also, unless it's been messed with, your barrel is marked as a 9mm Luger barrel.

The ammo specification was NOT stronger back in the day. That is a myth. You should not use higher power ammo like +P or surplus machine gun ammo in a Luger, particularly an older one like yours. Just standard velocity 9mm with ball (jacketed) FMJ bullets. The recoil spring should have 19 coils. Don't go messing with this until you properly determine the right ammo for this gun.