If I could get a source on the small, 7.62x25 and large, higher power (read: 7.5x55, 303, 7.62x51, 7.62x54r) Berdan primers, I'd definitely be interested in this.
The ones we can get now are for 7.62x39, or so my reading tells me.
Most of us reload for accuracy/cost over plinking, and my feeling is that all the Berdan primed surplus is getting scarce until things change in the Russia/Ukraine situation.
(and my understanding is that when the GP11 supply we have now dries up, that's it).
Preheat works sometimes, which just adds another level of pita. But in my mind worth it, if you can reuse it, haven't seen much better brass for the m305 as far as longevity goes.
I'd be interested in .308/7.62x51.
I live within GVRD.