These are the official Lake City AAP loads for the M80 (7.62x51mm NATO) with the 147(-3) grain bullet:
Early load = 41 grains of IMR 4475 (equivalent ballistically to IMR 3031, but IMR 4475 granules are smaller)
Current load = 46 grains of WC846 (BL-C(2) is the equivalent canister propellant to WC846). WC846 also is available as surplus propellant.
M80 mean MV = 2750 +/-30 ft/sec at 78 feet. CCI 7.62mm NATO-Spec #34 Military Primers are recommended.
COAL = 2.80"-0.03"
The above powder charge weights are just nominal charges. The critical standard is the velocity at 78 ft.
For more practical chronograph purposes, with the 147 gr bullet in question, that works out to a velocity of 2800 fps at 5 yards.
I'd start with BL-C(2) at 45.5 grains and work up to the specified velocity.
Just as a follow up, I pulled a couple 1980 M118LR rounds and checked the powder charge. 42.5 gr of a stick powder with grains ever so slightly shorter than IMR 4064. Never having seen Varget, it might be that, but the velocity out of my 26 inch barrel is significantly faster than the chart above shows.
BTW, all the sources I've ever seen show the load with the 175 gr SMK always identified as M118LR. Special Ball doesn't appear in /the labels and apparently was applied to the 168 gr M118 load before it was designated as M852.
Now then, the 173 gr match bullet started out with the .30-06. It's easily identified by a pronounced meplat. It also became the standard military match bullet when the DOD converted to 7.62 x 51 mm. Published load M118 data back in them thar days was 40 gr of IMR 4895 at an OAL of 2.800 inches, plus 0.010 inches tolerance.
It's complicated but M118 Special Ball was just late production M118 Match after M852 Match was introduced as the new Match load.
There was also an M118 Match load using the 168gr SMK, but it was an unofficial load where the 173 gr FMJBT was pulled and replaced with a 168 gr SMK, and it was called "Mexican Match".
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The complicated version of the story and the evolution of M118:
The original XM118 Match load used a match grade military case produced by Lake City, the No. 43 primer, a nominal charge of 42 grains of IMR 4895, with the same 173 gr FMJBT used in M72 match ammo and a velocity of 2550 fps (100 fps slower than .30-06 M72 Match). XM118 Match was introduced at the 1964 National Matches, the first time match grade M14s competed against Match grade M1 Garands.
The subsequent M118 Match load used either a nominal charge of 44 grains of WC 846 powder or a nominal charge of 42 grains of IMR 4895, with IMR 4895 being used exclusively by 1970. M118 Match was well regarded in terms of accuracy and was used with great success in Vietnam in M40 and M21 sniper rifles.
The problem with M118 was three fold. By the early 1970s the tooling used to make the 173 gr FMBT was getting worn and the bullet weight varied by as much as 2 grains. Lake City also started loading it in a standard case rather than match case, and started using the No 34 and No 36 primers rather than the No 43. The end result is that the accuracy of M118 Match degraded to around 2 MOA.
Back when I shot service rifle competition, I found that the issued M852 shot quite well in my M1A (1 MOA), while issued M118 Match would hold 1 MOA with a good lot and as much as 3 MOA if you got a bad lot - when you needed at least 1.5 MOA to be competitive. Ironically enough I also found that the M72 Match was consistently accurate, mostly due to being made before the bullet tooling was excessively worn. The newest M72 Match I ever saw was made in 1969. Operationally speaking, as M118 Match quality degraded sniper units needed to test and select more accurate lots of M118 Match , which could shoot 1 MOA or a bit better in an M40 or M24.
The USMC maintained a sniper program after Vietnam while the Army did not, so the US Army Marksmanship unit had to carry the Army's weight in rifle and ammo development. They also found the M118 Match ammo to be lacking and also found that pulling the 173 gr FMJBT bullet and seating a 168gr Sierra Match King produced much better results back down around 1 MOA again in an M14 or M1A, and this was called "Mexican Match". This led to the development and adoption of M852 Match ammo using the 168gr SMK in a match case with the No 43 primer in the early 1980s.
The problem was that the 168gr SMK used a hollow point bullet, and while not designed to expand, the legal opinion at the time was that M852 Match violated the Hague Accords and could not be used in combat.
Since M852 was the new match load, M118 Match was renamed M118 Special Ball. However it had the same quality problems as the late production M118 Match but it soldiered on until M852 was approved to sniper use in the early 1990s. Even then, M852 wasn't ideal as the 168gr SMK was designed for 300 meter international competition and had a 13 degree boat tail that didn't transition well to sub sonic velocities, and at the M852s rather low 2550 fps velocity, it wasn't all that accurate past 700 yards at a time when the effective range of an M24 or M40 was considered to be 800.
This led to the development by the USMC in 1993 of a new sniper round. This used a 175 gr bullet developed by Sierra using the same 9 degree boat tail as the 173 gr FMJBT. They also increased the velocity to 2,580 fps. It was a new round, but calling it a new round would require a new type classification and acceptance trials that would cost more time and money than the USMC wanted to spend, so it was called the M118 Special Ball Long Range, or M118LR. The round used what became the 175 gr SMK, a match case, a No 43 primer, and a nominal charge of 44 grains of WC 750 and it went into full production in 1998. M118LR pushed the effective range of the M40 and M24 variants out to 1000 yards.
M118LR was accurate but the propellant proved to be too temperature sensitive. The result was the US Navy SPecial Warfare Center started developing a replacement, testing 15 different bullets and 20 different powders, before selecting the same 175 gr SMK. They also farmed production out to Federal, which uses a Gold Medal Match case, and a Federal Match primer, with a powder that I strongly suspect is RL-15 or a close copy.
The new round then got a new twist on the old name for the same reason the USMC stuck with the M118 classification - M118 Special Ball Long Range Mk 316 Mod 0, or just plain Mk 316 for short. It's half MOA accurate and is temperature stable with a change in velocity of only 21 fps from -25 F to 165 F, compared to 227 fps with M118LR.
