It is my understanding that the M118 LR in 20 boxes was used for "squad designated marksmen" in the first Gulf War and then, later on, in Iraq and Afghanistan. The ammo in the "bulk box" based on my understanding was overrun ammo that was produced at Lake City with the same specs as the M118 LR in 20 round boxes.
I am an attorney and got a call one day from the secretary for one of our Circuit Court Judges regarding her son, who was at that time a Lt. Col. in the 101st Airborne at Ft. Campbell. The squad designated marksman (SDM) program had just been initiated and all of the marksmanship trainers had deployed to the Middle East. She told me that her son was looking for help from civilians who were high-power rifle shooters and who had experience with the M-14 platform.
They needed someone for a week to ten days to train and familiarize selected soldiers with the M14 platform and Leupold scopes that were to be used in the program. My schedule was such that I could not take that much time off but, my shooting partner, who was retired and a Distinguished Marksman, on the M14/M1A platform, was available. Between the two of us, we had over sixty years of service rifle competition experience but, neither of us were veterans.
At that time, my shooting partner had no experience with rifle scopes so, we developed a plan. He would be on sight and if any issues arose regarding issues with the scopes, he would call me on my cell phone to discuss the issue. Prior to him actually going to Ft. Campbell, we met for me to give him a briefing on scopes, adjustments and potential issues.
The plan worked very well and he did an excellent job in getting those troopers trained up on the M14 platform and the optics. As I said, he is/was and engineer and worked on aerospace projects from Apollo to the Space Shuttle. That being said, one of the first issues was that due to the shortage of true National Match M14's, two SDM's were assigned to one rifle each. He couldn't figure out why when shoot A had zeroed the rifle for themselves, that the zero would not work for the second shooter.
He and I spent a couple of hours in conversation for me to convince him that no two shooters would ever have the same zero due to differences in size, length of arms, necks, etc.... He finally got it and the solution was for each shooter to keep a data book for them to make the necessary corrections from their fellow shooter's zero in order to put their zero on the rifle/scope combination. It worked.
We talked every day and most evenings when he returned from Ft. Campbell to discuss issues and trouble shoot problems. It worked great and I enjoyed and appreciated the opportunity to help him and especially the SDM program. The ammo that was initially used in the program was the M118 Special Ball. This was essential the same a the M118 National Match ("White Box") ammo but, the primers were crimped. This round, as most of you know, was loaded with the 173 grain FMJ, match bullet.
The later M118 LR rounds, as reported by others, was loaded with the 175 grain Sierra Match bullet. That ammo was introduced later in the Middle Eastern conflict.
All, in all, the SDM program seemed to work very well. My shooting partner kept tabs on many of the troopers that he personally met and trained. I had no direct contact with those fine men and women but, appreciated their service and sacrifice. The SDM from that unit suffered a noticeable rate of casualties but, gave better than they got.