Thursday I placed an order for a 22" Contender barrel in Gary Reeder's 257 Raptor which is based on the 204 Ruger necked up and improved (think Ackley). From what I have read it appears this round is very similar to the 257 Kimber. I've got a good quanity of IMR 4064 and I would like to use this powder to fireform the brass and barrel break-in. From my various manuals (looking at 223 Rem, 222 Rem Mag, and 6x45)it appears that 24.0 grains would be a safe fireforming load with 100 gr bullets. What do you think? Thank you.
Alan
