I fail to see why 300-400 fps will burn your barrel out any faster. It is not speed that burns your barrel out it is more fault of the shooter that will burn the barrel out. I have talked to several barrel manufacuters and I have shot many thousands of 55gr BTs and I have had several 243s all shot extremely well even after 3000rds of BTs. You are not going to burn your barrel out shooting 55s. You will shoot out your barrel if you shoot and get your barrel hot enough too cook eggs and don't give it a chance to cool. Your 70s will burn out your barrel just as fast. HAPPY HUNTING
