The gun I bought is an Armalite that was originally a 300 RSAUM....it has since been re-barreled in a 300 WSM. I own a 300 RUM and have some idea of its capability. This is the first time owning anything like this in an AR10 platform. I was wandering about performance? Barrel life? Just anything that may or may not help with this. One thing I have read is to stick with the 150-165 gr bullets instead of the heavier loads for jamming reasons....is there any truth to that?