I have an old Caldwell Rock BR rest, never used it since the little black sandfilled bag they use is crap when I had my old BR 6. 5 x 284, which I sold. I dusted it off and I now use the A 5 McMillian stocks with the picatinny rails and a bipod. I am looking for a better BR rest with an adapter that I can use for my A 5 stocks, or a type of bullbag compatible to fit A-5 stocks or a BR adapter in the existing Caldwell Rock BR rest. I plan to use it for F Class. Hopefully you guys can lead me in the right direction on picking BR rests as well.