The standard issue accuratized ammo is M118LR. I don't know the weights and grains, you could look it up. Lake City makes it.
"The standard issue accuratized ammo is M118LR"
Both are issued as the JAG determined that the Sierra HPBT is not designed to expand. By the way, the M118 load uses the same 173 gr FMJBT that was developed for use in the 30-06 National Match ammo, designated M72, about a hundred years ago. Only the Finnish D46 bullet, in use to this day in the 7.62x54r has been in use longer.
The Mk-11 is mfg. by Knights Arms. and "built" by the same armorers @ Quantico who build our bolt-action stuff. We use a modified version of the Schmidt & Bender 3-12 x 50 Police Marksman LP II scope. It will become standard equipment on all .308 and .50 caliber USMC sniper rifles, including Mk-11's. Unertl and Leupold fixed 10x scopes are removed/replaced as we send weapons in for maintainance at the higher echlon.
The Mk-11 was originally designed for and is primarily in use as a DMR (designated marksman rifle). It is slated to replace the aged and problematic M14. The M14 (M1A)is used by mostly security forces, FAST Co., and some DM's in the field. Cost and reliability is an issue with the M14's.
In my STA Plt. we still used the M40A3's and M82 for our precision firing and Scouting. The Mk-11 is mainly used when a mission requires sustained accurate fire. 80% of the Mk-11's you will see in the field are used by DM's in the line co.'s. While they do not hold the billet of an 8541 (Scout/Sniper) they do attend a shortened version of the school... scopes, target detection/aquisition, range estimation, counter sniping, sniping... etc. They do not go through the fieldcraft portion of the school.
As far as the brass being seen upon ejection, it's not an issue. When we load bolt actions we load full, and let casings fly as we cycle the bolt manually, it's the same thing. When I fire at a target up to and including 1200 yds. out, will it ever see the brass? As far as other people in my AO seeing an ejection... that's taken into account when selecting a hide.
And as far as the AR & Mk-11 comparisson goes... well, the USMC selected the Mk-11 from Knights. Enough said.
The Mk-11 has it's place, but IS NOT and will never be a replacement for our bolt action rifles.
USMC Scout Snipers will always be just that... Scout Snipers.