Not sure if you caught this one:
118When I was active duty the original M-118 SB (173 grain FMJBT) was standard issue and I shot plenty of it out of my issued M-21 and never had any problems with the operating system. I will say the earlier M-118 SB was "average" when it came to accuracy. In addition to zeroing and training with the M-118 SB we also did the same with 168 grain Federal Gold Medal Match, and if we had the choice it was actually what we shot.
I believe the new M-118 LR (175 grain SMK HPBT) is an improvement over the original M-118 SB. I have only had the chance to shoot a couple of boxes of the new M-118LR and it did seem to perform better that the original M-118 SB, however it still was not as good as the Federal or Black Hills Match Ammo.
Also note per the post above, chances are any M-118 LR that hit the market recently is either “XM” or “PD” stuff which is basically a quality reject. While some quality rejects may be simple cosmetic issues and will shoot just fine, you may also find some with some significant mechanical problems that could impact performance, hence the “Training Only” stamp you will find on it.
Good Luck,
“Capt Richardson”
PS: it would seem that The Gooch has the new 175 grain M-118 LR and FNBrowning has the older 173 grain M-118 SB.