Smith & Wesson Forum - View Single Post

lrrifleman · 03-18-2017, 09:51 AM

@Tanklegacy,

I am afraid that you may be expecting more from your AR10 than it is capable of delivering. I am not knocking your equipment, but basing my comments on almost 30 years as an NRA competitor.

After an accident 10 years ago left me disabled, I can't shoot service rifle matches any more, I am shooting F class matches now. I now shoot the following load in my Remington 700 BDL Varmint at 600 yards and 1000 yards, and it should be safe in your AR10, if you don't load via the magazine. I have replicated M118LR ammo with this recipe: 41.8gr IMR4895, CCI benchrest primers, and Sierra 175gr MatchKings loaded a hair long, in GI Lake City cases, with a 24" barrel muzzle velocity of 2558 fps. WARNING: this load tailored to MY rifle!

Things to keep in mind:
1. Your cartridge overall length is limited to the size of your magazine, IFF you plan to feed from the magazine. If you plan to load every round singly, you have no limitations.
2. You need to know your rifle's leade, if you are going to load long and feed each round through the ejection port. This can be achieved using a Stoney Point style C.O.L guage.
3. You need to both chronograph your load, and shoot a waterfall target noting vertical displacement at distance. Vertical displacement and minimal extreme velocity spread indicate your load with the greatest accuracy potential!
4. Back when I was able to shoot service rifle, I shot a M1MkII Garand and an M1A. I tried to load match grade ammo with my Dillon 550B using IMR4895 (stick powder), but I could not get consistent weight charges. Consider a single stage press for precision ammo using stick powder.
5. You need a barrel length that will allow the powder to burn completely to give maximum velocity. You want the bullet to stay supersonic at target, you may be short changing yourself with an 18" barrel. I have been able to keep the aforementioned load supersonic at 1000 yards with a 24" barrel in my Remington 700 Varmint, but it goes subsonic by 1050 yards.

Best of luck!