Originally Posted By DakotaFAL:
Back in the day M118 Special Ball was issued as a sniper round for the M14, M21, M24 and M40A1 rifles and as a Match round for service rifle competition. It used a 173 gr FMJ - the same bullet used in .30-06 M72 Match ammunition - and represented a strict interpretation of the non expanding ammunition requirements of international law. The propellants used included both IMR 4895 and WC846 for a peak pressure of 50,000 psi and a velocity of 2640 fps, the same velocity as M72 Match. Charge weights are pointless to discuss as at that level of accuracy, the precise charge will vary with the powder lot, even with canister powders. The accuracy standard for M118 was no more than a 12" spread for a 10 shot group at 600 yards.
The potential issue with accuracy and an FMJ is the exposed base of the bullet. It is a lot harder to maintain perfect dimensions and consistency in the base of an FMJ and the dimensional accuracy and consistency is important when the bullet exits the muzzle. That led to the development of M852.
M852 was issued in addition to M118, for use in match grade M14s and civilian M1As. However it was intended only for Match use and training and was prohibited from use in combat (at least initially). This round used a 168 gr Sierra BTHP Match bullet. The hollow point design in this case was intended to allow far more precise dimensional control of the bullet and was not intended to expand. And in point of fact it does not expand and it has become a standard for sniping in police departments and in some militaries.
M118LR was, as the LR suggests, intended to push the effective range of the 7.62x51 from about 800m to 1000m. It uses a 175 gr Sierra BTHP at 2600 fps measured at 23.8m from the muzzle (a standard in all the above velocities) and consistent with a more liberal and more enlightened interpretation of non- expanding ammunition to include bullets other than FMJs, it is approved for use in combat.
Thanks for the history. I have a 460 round ammo can of M852 and wondered why all the brown boxes say "For Training Use only" on them.