If you didn't see the first thread I talked about where I had a SIG 556 SWAT that shot the 1st shot from a magazine 4" to the right of the remaining shots. It did the same thing with 2 different mags and even if you shot 1 shot at a time without a mag they were 4" or 4 MOA at 200yds to the right.

Originally I thought it might have been the Swat rails binding on the receiver so I relieved them even more than I had before and went to the range.

The gun shot the same.

I took the Swiss Handguards of an earlier 556 that I had and put them on the rifle.

The gun shot the same.

My earlier 556 had some Swiss produced parts including the Bolt. Here's a pic of a US and Swiss bolt side by side:



Guess which one was made in Switzerland..........


So I put the Rails back on since it obviously wasn't the handguards and simply swapped out the Swiss bolt and bolt carrier into the 556 SWAT.

The next 3 shots went into less than 1/2" at 100yds dead center. 10shot group at 100yds was less than 1 1/2" with mostly vertical as the barrel heated up. This is with an Aimpoint M-4 red dot sight and no magnifyer.

The Problem was obviously with the bolt.


The US Bolt functions just fine in the other gun. It doesn't show the same 1 shot 4" right that the SWAT rifle did but it doesn't seem to be as accurate as it was before. Now it's shooting 2 1/2 to 3 MOA or thereabouts. I haven't shot it in a while and don't remember exactly how it shot before with it's original bolt.

So I was able to solve the problem with the SWAT but still have another 556 that probably isn't shooting as well as it could. I like the SWAT rifle better so will probably leave the bolt and carrier in it.

So the SWAT started shooting very well. Then the stock cover directly behind the reciever fell loose and won't stay attatched...........Come on SIG!..............................................................DJ

Here's the Stock Part that broke loose:




I gotta say I'm gettin pretty weak on SIG Quality control on 556 rifles.

I like the triggers and how smooth they shoot but having parts fall off a 1K+ rifle is BS quality control pure and simple........................DJ

I was fixing to buy one of these rifles,thanks for posting this,I will never look at another! I dont need to buy a POS

FN Scars cost more but are far superior rifles, you might consider them instead.............DJ

dang - i've have zero problems with mine

The local shop has one for 1999.99

can you imagine been sitting in the rack for over a year now..GOOD for the pos!I gotta H&R and a remington that will shoot better than that...

That's why my SIG is an AR....

And now don't start the BS arguments about direct impingment etc-all PC garagbage talk by (mostly) folks who have no where near teh real esxpereince.

ARs work and work hard.

20 inch CM 1-8 twist with collapsible stock and that's about all you ever need in a 556 (5.56mm NATO I mean)

Prove otherwise!

Forgive my spelling-nerve damage acting up again...

I will say that the Sig 556's do have some nice things about them. I like how smooth they shoot, they have excellent triggers and all three of mine have been 100% reliable.

It's just very dissappointing that US SIG has allowed poor quality control and cheap bits to mess up what could be a particularly fine rifle.

I saw some other posts that may show even more exactly the problem - a miss-milled spot on the trunnion that may be the overall cause of the issues I was having. If grinding off that spot makes the original bolt shoot as well as the Swiss made one I'll be happy.

A reliable Semi-Auto folder that shoots 5 shot MOA groups is worth having. I just wish you didn't have to fiddle so much to get there. If SIG had their QC act together you wouldn't..................DJ

quote:

Originally posted by djpaintles:
FN Scars cost more but are far superior rifles, you might consider them instead.............DJ

And the reason they cost more is ......................

probably because they have better QC and they work !

IMHO, whether a gun costs $1, $1000 or $10,000, if it doesn't shoot or
falls apart as per the SIG above, it's useless.

The proliferation of Black guns over the last year has seen some come
to market that in reality are not up to standard.

.

DJ,

I had a similar problem many years ago with a metric FN FAL.

I changed the bolt carrier and bolt several times, trying one with the other, until I got a 1 1/4 to 1 1/2 MOA rifle.

Not much you can do with some semi autos other than change parts around.

Off topic maybe but I had a similar problem with one of the first SR-25's. Its a long story but the pressure on the bolt carrier of a full or half full magazine changed point of impact substantially.

I pointed this out to Gene Stoner, they worked on it, and never completely resolved the issue of a cold vs hot point of impact, but vastly improved it.

If you used ten rounds in the mag it wasnt a problem.

Whod a thunk it??

Thanks for sharing your experience.

Andy