Sig 556 Rifle

alaskasteve · 01-05-2008, 05:09 AM

I love the rifle but the rifle does not always love me. The Sig 556, gas piston semiautomatic rifle. 16 1/2" barrel, 1-7 twist. I am having problems getting good accuracy out of the rifle. I can get no smaller than 3 MOA, now 3moa is not terrible accuracy for a tactical rifle, yet I would think that a 1300$ rifle from a maker like sig, would shoot boringly accuratly. Now I am on my third sight, i started with a Bushnell Halo, I got 3 MOA, I put a Meprolight 21 reflex sight, again 3 moa. I currently have a TAO1NSN "Special Forces" ACOG on it, yet still 3 moa. I did get one group that was 2.5 moa, but that was only once. I Thought that at first it was the ammo, the 1-7 twist is fairly fast, so I thought that the cheap PMC and the not-so-cheap hornady v-max at 55grs was part of the problem. I have tried Black Hills 68gr HP Match, 70gr handloads w/ varget, 62gr FMJ Match handloads. Black Hills 55gr FMJ, Wolf 62gr Hp, Wolf 55 FMJ, PMC 55gr FMJ, Americal Eagle 55 FMJ, Military "green tip M855 Ball" winchester 55gr FMJ 5.56 nato. S&B 62 FMJ. So now I am pretty much stumped, what is up with this rifle? I know I am not the best shot in the world, but why would a rifle simply not be ableto do better than it is? My home built Ar-15 16" GG&G Barrel & Meprolight 21, will out shoot the SIG/ ACOG (4x) every time. So does anyone have anything else I can try before I get fed up at send it in to the factory? I had to have missed something, but I am at the end of my capibilities to fix whatever is the problem.
Steve

Mooseman684 · 01-05-2008, 02:20 PM

I am going to assume you are benchresting that rifle, and from the ammo you have tried, the barrel should be broke-in by now.There are so many factors to look at that affect accuracy, such as Temperature, humidity, wind velocity, and ammo used... I would first check my scope mounts for tightness and even torque on the screws then , remove the flashhider and check the muzzle crown, and touch it up a bit. Re-install the flashhider and test fire...Your rifle should do well with the heavier bullets with a 1:7 twist...you may have to try different velocity loads to find the best one for accuracy, try slowing some down in velocity when you load up some to test.I prefer Sierra Bullets for accuracy testing...Match kings seem to be best as far as accuracy goes in my opinion. keep us posted!
Rich

01-05-2008, 05:09 AM	#1
alaskasteve Member Join Date: Oct 2007 Location: Alaska Posts: 20	Sig 556 Rifle I love the rifle but the rifle does not always love me. The Sig 556, gas piston semiautomatic rifle. 16 1/2" barrel, 1-7 twist. I am having problems getting good accuracy out of the rifle. I can get no smaller than 3 MOA, now 3moa is not terrible accuracy for a tactical rifle, yet I would think that a 1300$ rifle from a maker like sig, would shoot boringly accuratly. Now I am on my third sight, i started with a Bushnell Halo, I got 3 MOA, I put a Meprolight 21 reflex sight, again 3 moa. I currently have a TAO1NSN "Special Forces" ACOG on it, yet still 3 moa. I did get one group that was 2.5 moa, but that was only once. I Thought that at first it was the ammo, the 1-7 twist is fairly fast, so I thought that the cheap PMC and the not-so-cheap hornady v-max at 55grs was part of the problem. I have tried Black Hills 68gr HP Match, 70gr handloads w/ varget, 62gr FMJ Match handloads. Black Hills 55gr FMJ, Wolf 62gr Hp, Wolf 55 FMJ, PMC 55gr FMJ, Americal Eagle 55 FMJ, Military "green tip M855 Ball" winchester 55gr FMJ 5.56 nato. S&B 62 FMJ. So now I am pretty much stumped, what is up with this rifle? I know I am not the best shot in the world, but why would a rifle simply not be ableto do better than it is? My home built Ar-15 16" GG&G Barrel & Meprolight 21, will out shoot the SIG/ ACOG (4x) every time. So does anyone have anything else I can try before I get fed up at send it in to the factory? I had to have missed something, but I am at the end of my capibilities to fix whatever is the problem. Steve

01-05-2008, 02:20 PM	#2
Mooseman684 Super Moderator Join Date: Dec 2005 Location: Alaska Wilderness...Currently in Holiday, Fla. Posts: 10,999 Images: 2	I am going to assume you are benchresting that rifle, and from the ammo you have tried, the barrel should be broke-in by now.There are so many factors to look at that affect accuracy, such as Temperature, humidity, wind velocity, and ammo used... I would first check my scope mounts for tightness and even torque on the screws then , remove the flashhider and check the muzzle crown, and touch it up a bit. Re-install the flashhider and test fire...Your rifle should do well with the heavier bullets with a 1:7 twist...you may have to try different velocity loads to find the best one for accuracy, try slowing some down in velocity when you load up some to test.I prefer Sierra Bullets for accuracy testing...Match kings seem to be best as far as accuracy goes in my opinion. keep us posted! Rich __________________ You know you might be facing your doom,when all you get is a click when you're expecting a BOOM!