1971silversurfer

I use 123 grain projectiles in my 260 Ack Imp. Primarily SST and Scenars. 

I don't suppose you still have the .308 barrel ?

R Macleod of Tain, have listed on their website a .308 barrel; for the R93 no mention of any fluting through. hope this helps.

Good news Mark, best wishes,

lovely insight into how a gun is built...for us mere mortals!!!