I've been promised some 257 Weatherby brass, I have no need for it as 257. I do have a need for 7x61 S&H. The 257 is 3mm longer than the Sharpe and Hart.
Considering full length sizing in the 7x61 die with the de-cap/sizing plug removed. Then powder/toilet paper/plug of some kind and then make a mess of the backyard.
First this is old brass. Should I anneal because of age hardening/unknown number of firings before starting? Definitely going to anneal before loading for the S&H.
Any guesses on a starting load for the fire forming and best powder to use other than the generic fast pistol powder?
Wax plug in the neck or just toilet paper wad? Toilet paper wad worked well for me going 30-30 to 38-55 but this is much stiffer brass, don't know if it's going to need more pressure to get the neck blown out.
Anybody done this? Or a similar case conversion?