Wanting to build a trainer. Looking for 20-26in. Remy 700 threaded. Going from a 308 to a 223 so I am gonna need a smaller boltface. Dont know dick about swapping this over but I got buddies that do. Dont need anything special, but I want to simulate the same weight and length as my comp guns. MTU/M24/Hvy varmint. Send rough round count and pictures if you reply please