Is it safe to fire a vintage
 

Luger with modern factory ammo? I read on a P.38 forum That wartime P.38 should never be fired with modern ammo. The slide will break into in the open area. It suggested you buy a P1 slide and forged locking block then shoot your treasure?
Steve

As long as the modern ammo is standard velocity it should be OK. Different OAL from different makers may be encountered, and this can affect feeding.

What you need to avoid is +P, +P+, or NATO marked ammo. Steel cases are obviously harder on the extractors.