I have just got back my 223AI with a 7.7 twist ABC barrel hoping that they work out for 600yds well. I have some Rem.SA’s that have been blueprinted and waiting for a project. I have one in 308 bolt face and another in 223. I’m leaning towards the 308 bolt face and looking for choices but I don’t have to destroy barrels in my quest to make that bullet/cartridge combination work....distance would be 500-1000yards.Purpose... because!!! Also ,what twist would you suggest .