Having trouble with accuracy of my 556

Hello everyone, i really love shooting my 556 but im not really loving the accuracy im getting from it. Now i dont claim to shoot tight ass groups all the time but i can get them pretty close. I have only had my 556 for about a month now and im lucky if i can get about a 3 inch group at 100 yards if im lucky. Ive been playing around with my ammo and i have only been shooting 55 grain bullets from several different manufacturers. I thought i read on this forum a while back that the 556 likes the heavier bullets. Any one have any thoughts on this? Any help would be appreciated.

 

Try different ammo for starters. Mine happens to shoot 55gr PMC well but it didn't like XM193 or PPU193. My 556 gets the best groups with PPU 75gr OTM ammo. Yours may be different.

H

 

Little late to the conversation but--
heavier bullets - Thats what I read also because of the tight twist.
I'm still testing mine out and been sighting in a Burris scope and
Sig red dot. 55 and 62 are doing very well. I have some 75's that I'll be
getting to.

I only have about 500 rds through it so far and feel its getting better with age.

 

piling on here.

over 7,000 rounds and groups in the 2-3" range at 100-150 yards are common.

These aren't tack driving accuracy rifles, they're assault rifles. 2-3" groups puts every bullet in the heart. Not flamin' just sayin'

 

Yes, the 556 is not a sniper rife, but my Swat Patrol (May 2012 build) could not shoot any better than 4.5 in. 100 yd. groups with any ammo, including Hornady Superperformance 75 gr. match. My Scar 16s shoots the 75 gr. match right at 1" 100 yd. groups, so I sent the 556 back to Sig to get it fixed a month ago. Hopefully, it won't take too much longer to get it back.

 

3" at 100 is not bad at all if you're shooting with a red dot and bulk .223/5.56 55gr ammo. Specifically, what optics or sights do you have on the rifle, and what ammo have you been shooting?

 

Check your crown, Mine was so bad Sig put a new barrel on it.

 

Through the years The 556 has been out I have read many complaints of the accuracy or should I say the lack of accuracy of the 556. Mine will not group any better than 2-3" at 100 yards with anything other than 52 grain SMK. I verified the 1:7 twist and had many conversations with Ullie when he was still with us about this. With the 52 Grain Smk's I can get down to 1.5" sometimes less @ 100 yards. I've tried everything 52's 53's. 55's 60's 69's and 77's with different powder loads with incremental changes in powder 0.2 grains. The rifle shoots best with 26.2 grains of W748 behind the 52 grain Smk's and CCI primers. I rarely shoot it sny more but I love my SIG 516 which was a sub moa right out of the box. Almost makes up for the fiasco with the 556.

 

Where in AZ are you located? I'd be interested in buying your 556 if you're unhappy with it.

 

I am so under water with what I have into the 556 There is no sense in me trying to sell it. I put Samson SIG Flip front sight, ARMS 40L rear sight, Magpul CTR butt stock, Swiss 551 hand guards Swiss front take down pin and bayonet lug. An EoTech 552 on it now had previously had a Night Force NXS 1-4X24 on it. Additionally I paid top dollar for it since I bought it when they first came out. As long as I can get 1.5 to 2" groups with the 52 grain SMK's and the 552 EoTech I will have to live with it

SIG can build a great rifle as my SIG 516 will shoot shoot 1 moa groups with just about any thing I put through it. The 556 just was up to the usual SIG quality and performance .

 

+1 on more grains and changing ammo manufacturer

 

I recently bought a 556XI and I have to say I'm not impressed with the accuracy either . It took two trips to the range just to get it closes to being sighted in . I had to adjust the windage almost all the way to the right to keep it from shooting left. 3" groups at 50yrds , more like 6"-8" at 100yrds. It has never misfired or jammed thought

 

every US make 55x series weapon I have ever owned sucked with 55 and 62 grain ammo. Load up some 75-77 grainers and it will bring your accuracy down to 2-3 moa @100

 

if your barrel is a 1 and 7 twist use a heaver bullet , a larger grain will make the diffrence