Quite a discussion and research has been done other places. Originally the M118LR used IMR 4895, when Remington Had the contract. When Winchester Corporation took it over they switched to WC750, which did not do well as far as consistency in desert conditions (Iraq). As of 2007, Federal won the contract and switched to RL15 with the above changes to the case and also the primer, as well, using their Gold Medal Match Primer. I believe Federal still has the contract but that it has been superseded by the above Mark 316 Mod 0. I like M118LR, but it is a hot load, and I have some pretty high muzzle velocities on my chronograph, so I keep it in reserve, or to compare to my reloads.