M118LR is the long-range military ammunition that uses the Sierra 175-Grain MatchKing bullet. The LR (for Long Range, originally for sniper systems) distinguishes it from the original M118 Match ammunition made with the old military M72 Type FMJ match bullet of nearly the same weight (174.5 grains with - 3.0 grains tolerance, 173 grains being the midpoint value). Alliant brags that Reloader 15 was chosen for this round, so the M118LR chamber should be optimized for that bullet as far as bullet jump goes. If you want, you can buy new production by Winchester or by IMI to make comparisons to your own ammo developments.