5.56 Ammunition for Competition Shooting

[klane60]

I have a Smith and Wesson  M&P AR-15 with a 16”  1:9 Barrel.  I am looking to shoot EIC competitions 200yd, 300yd and 500yd.  What ammunition would you recommend.  I am looking at the following:  I’m pretty sure a 55 grain would not do well at the longer range.

70 gr. GMX® TAP® BARRIER
Recommended Rifling Twist Rate: 1:7

62 gr. TAP® BARRIER™
Recommended Rifling Twist Rate: 1:7 to 1:12

[kmitch200]

A 1 in 9 barrel will shoot 62gr bullets just fine.
Don't get married to the Hornady line until you've tested them fully in your gun. It may *love* them...it may not.  My M&P T doesn't particularly like Hornadys for groups but that doesn't mean yours won't. The only way to know for sure is to send some down the pipe.

You should be able to shoot (according to Berger) bullets up to 73 gr but theirs is lead/copper, not homogenous like GMX, Barnes, Nosler E-tip, which are long for their weight. GMX @ 70gr is probably not gonna cut it in 1:9.

http://www.bergerbullets.com/products/target-bullets/

Unfortunately unless you reload or have a friend that does, you're buying ammo in the caliber that just had a massive run on it due to the DC Jugheads. SGAmmo has some Federal Gold Medal Match 69gr - $21.95 and TDS ammo has some Hornady 62GR TAP URBAN that is $14.50 for a box of TWENTY. 
OUCH!   

[MikeBjerum]

Everyone I have talked to that shoots long ranges with anything .223 is that to go above 65gr you need a 1 in 8" and above 70gr you need 1 in 7".  The notes I have jotted from talking to these shooters say I should start at 62gr in my 1 in 9" barrels and look for the round that works best.  Lots of bench time that I have not invested, because we have very few competitions in this region.

By the way, these shooters also talked about 5.56 chambers reacting different than .223, so that throws one more wrench in the works for bench testing.

[les snyder]

I'd start with a 69grain Sierra and Hodgdon Varget...