Ammunition
I will discuss .223 and .308 here
as they are the most commonly used in service rifle competition. In .223 for
reduced course of 100 yards match bullets in the 52 to 62 gr. weight class
have proven to be the most accurate when fired out of AR-15 barrels
with 1-7, 1-8 and 1-9 twists. Winchester or Lake City cases with match primers will often yield 1/2 M.O.A. accuracy.
Certainly anything over one M.O.A. would be disappointing.
Due to liability, no load charges will be given here. For the 200 yard line, match cartridges using Sierra's 69 gr. BTHP match bullet or Hornadys 68 gr. BTHP match are a good bet. For the 300 yard line Sierra's 77 gr. BTHP match and Hornady's 75 gr. BTHP match are a good choice. For the 600 yard line Sierra's 80 gr. BTHP match is a good place to start, here you will be much more limited.
Factory Ammunition
For those who do not reload, factory match ammunition new or remanufactured from Black Hills and new match ammunition from Federal is the way to go. This ammunition is available loaded with most of the above mentioned bullets. Once you find what your rifle "likes" consider buying in quantity to offset the expense. All of the above mentioned bullets are not meant to be the definitive choice, they are what has proven itself many times more then not to be the best choice and are by far what the bulk of service rifle competitors are using.
What Your rifle "Likes"
The only way to know what your rifle "likes" best is to try it. The AR-15 can be very ammo specific and can vary in what will yield the greatest accuracy in an individual rifle. There is no magic or tricks, you will have to try to know.
Economical Ammunition
Ammunition the likes of Winchester white box, Wolf and foreign surplus just does not cut it. Some may disagree here and there may be rare exceptions but I have not seen it. I have seen standard AR-15 rifles shoot over 3 M.O.A. with the economy ammo mentioned above only to group sub M.O.A. when using the recommended ammunition stated.
.308 ( 7.62 X 51 Nato )
The .308 in match configuration is much easier to load for. It is said there are a few loads and if a .308 rifle will not "shoot" with one of them the rifle will not "shoot". This is pretty much the case but as always there may be exceptions. For the purpose of our discussion here these loads will be for match accuracy up to 600 yards in the M-14 / M1-A rifle.
The premiere bullet here is the Sierra 168 gr. BTHP match. The bullets are loaded in match cases the best of which are Lapua, Federal (no longer made) Lake city (can be hard to get) and IMI. They should be primed with match primers (I prefer Federal) The powders are IMR 4895, 4064 and Win. 748. Many other powders can be used with good results.
The cartridges should be loaded no longer then 2.830. Each powder charge should be weighed. The cases should not be used more then 3 or 4 times. You will hear of others using cases many more times but you would do well to heed my warnings here. A crimp should not be used with this load and should never be used with match ammunition.
With the Sierra 168 gr. bullet you are looking for 2550 FPS. This is what is known as the "National Match Load" it should be considered maximum and should not be exceeded. This load should yield sub M.O.A. in a match M-14 / M1-A rifle.
Factory Ammunition
For those who do not reload, new
commercial ammunition from Federal and new or remanufactured ammunition from
Black Hills utilizing match bullets from Sierra and Hornady can be used. Surplus, USA, UMC, Win. white box etc. will not yield match accuracy.
Questions?