SB1 frame with chamber inserts?
I saw some pretty interesting chamber inserts for sale, where you can convert your break action shotgun to shoot centerfire pistol rounds. I have an pardner 410 on an SB1 frame, and I know from the FAQ that the SB1 frame is meant for lower shotgun pressure levels and NOT centerfire rifle calibers.
The insert I am looking at is for a .380 pistol round. The .380 pressure is listed at 21,500, while 410 makes about 14,000. Would the .380 be safe to shoot from an SB1 frame? What are the safe pressure limits for an SB1?
Also, from what I understand the SB1 and SB2 can have different firing pin sizes? Would the SB1 firing pin work with a centerfire pistol cartridge?