I never shot the rifle "hot" and always kept the bore clean using the usual BR cleaning precautions. Put 1,000 rounds down the tube before accuracy took a noticeable turn south. The rifle was rechambered in 22-243 (plain) and has been shot very little since the rechambering. It appears that you can get nearly the same velocity with or without the AI conversion and any gain is not worth the effort to me any more.
Been always curious about this chambering. Got a 22 CHeetah MK 1 going this summer. 1-15" Pacnor on a Cooper model 22. Using the Lapua Palma brass and love it. Really only making a load manual for the cartridge for time being, for others to use who may want to try the CHeetah. Trying every conceivable powder and running up trough the charges recording velocity.
Think I may be on to a real doozy with H380 cuz hittin upper 4200's FPS and no pressure what so ever. Most every powder I've tried will push 52gr Watsons to 4200+ but show a little agitation around the head stamp. Not the case with H380 tho, I've yet to try the next slowest Hodgdon powder, H414...
That sounds like it will be some valuable load data when you are finished. Seems finding 22cal overbore load info is hard to come by, I know I looked for quite a while collecting data before I loaded a 22-284 round for development. I found H380 to be very temp. sensitive in a 22-250 I was working with, keep me posted on the finished data book as I would be interested in buying a copy.
Bob the nailer
one ragged hole...the quest for accuracy continues.
NRA Life member
Varmint Hunter Association member
American Gunsmith Association
Well my friend and myself have our 22-284's finished. We have completed barrel brake in and load development. We are shooting a 80 grain Berger with 55 grains of RL 25 and CCI primer with Nosler brass. Very pleased with the Brux barrel as it shows no copper fouling at all, and cleans up with only a few patches. The guns have both shot .25" 3 shot groups at 100 yds. MV is 3600-3613 FPS with a 27.5" barrel.