A review of the Sig 556R rifle

Discussion in 'General Firearm Discussion' started by halmbarte, Mar 3, 2012.

  1. halmbarte

    Active Member

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    I’ve been looking at acquiring a new rifle and fortunately have a friend who was willing to lend me his Sig 556R (7.62x39) rifle to shoot.

    At the range I shot this side by side with my Arsenal SLR-107FR. From prone I noticed the recoil was heavier on the Sig but the SLR does have a very effective AK-74 brake, so that comparison needs to be taken with a grain of salt.

    The Sig rifle feels more nose heavy to me, but isn’t bad or uncomfortable. In the accuracy department the Sig was getting groups of about 2MOA while the SLR was doing it’s normal 4MOA thing. I was shooting both with 2MOA Aimpoints mounted and using the same lot of Yugo M67.

    When shooting standing the recoil between both rifles was a lot closer in feeling. The SLR still had the advantage but again it had the brake to work with . I suspect switching the Sig’s stock flash hider for a brake would make for a major difference there.

    Biggest difference is the triggers: I’ve polished the stock Arsenal trigger in my rifle and it’s actually pretty good. The Sig trigger is very good: smooth first stage that comes to a clean second stage that has a crisp, clear break. I’ve seen trigger upgrades that cost $200 that didn’t feel that nice. I’ve owned a Garand and a M1A that had worse triggers.

    So, the Sig had been sitting for at least 60 days without having been cleaned after firing corrosive Yugo M67. I was thinking I was going to find significant damage to the internals. What I did find surprised me: The only real damage I could find was the recoil spring was pitted and some of the coils near the gas piston head have lost ~1/3 of their thickness and some pitting on the head of the gas piston itself.

    There were some rust spots on the gas plug and the gas block but those were removed by normal cleaning.

    And that was it. There was heavy powder fouling on the outside of the barrel where the gas systems vents, black carbony sludge in the receiver, and caked on carbon on the gas plug, gas tube, and gas piston. But overall, the rifle was in very good shape. The bore and chamber also had no observable damage.

    My Arsenal SLR-107FR would have been trashed in similar circumstances. I’ve seen the parkerized steel start rusting in 40 minutes here in Oregon and the hardchrome in the bore and gas block probably would have started peeling if let sit like that.

    Now to the pics:

    Corroded recoil spring and gas piston pitting

    Close ups


    Carbon staining of the gas plug, gas tube, and gas block.

    The center hole is for the gas tapped from the gas port. The two side holes are the pressure relief holes.

    Same arrangement in the gas block.

    Design details

    It’s easy to see the family history of the SIG550 series when you look at the bolt and connect the gas piston to the bolt carrier


    They welded a AK trunnion to the sheet steel upper? And they put the guide rails up there too?


    Standard gas setting

    Adverse setting (uses bigger hole in gas plug)

    That hammer spring reminds me of something...

    But the trigger doesn’t. It’s not AK based, it’s not Garand based, and it doesn't work like a AR15 either. It does have a very nice feel to it.

    Massive wear (not) to the forward receiver locking lug.

    Co-witness with stock irons and Aimpoint M4. The Aimpoint is on the QRP mount with the spacer removed (1.2” high over rail). To get a clean sight picture I found it necessary to rotate the rear sight to the open position.

    Cowitness thru the 200M aperture and the Aimpoint.

    This is as far forward as I could put the Aimpoint and still be able to remove the forward handguard.

  2. Hardwood floor guy

    Hardwood floor guy
    Active Member

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    and the moral of the story is.......clean your gun as soon as you get home or you will ruin a nice gun kids.
  3. Russianfist

    Sweet home, Oregon
    Active Member

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    I thought the moral of the story was to not loan out your sweet Sig to someone who's gonna run corrosive ammo through it and let it sit and rot as an experiment!
    mjbskwim and (deleted member) like this.
  4. halmbarte

    Active Member

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    Actually, the owner let it sit for months w/o cleaning. I cleaned it the same night I brought it home.

    Sorry I wasn't clear about that.


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