SIG 556

[terrylklun]

I recently purchased an A.R.M.S. #40 L-SP flip-up rear sight for my SIG 556.  I'm having trouble mounting it to the rail on the receiver.  After taking some measurements, I've come to the conclusion that the rail is out of specs per the MIL SPEC 1913 drawing.  (This was later confirmed by the local gunsmith.) The sight mounts fine on the three rails on the front handguard of the gun.  I've also mounted it with no no trouble on twelve different rail-equipped guns that either I own or my friends own.  Which leads me to believe that there is nothing wrong with the rear sight.  SIGARMS has been giving me the run-around.  Has anyone else been having this problem?

[drahthaar]

I am getting two of the 556's and I hope the are within spec's.  Did Sig give you an explanation?

[Pathfinder]

I don't know about specs, but I did get the 40L mounted on mine. As I recall, I did have to completely unscrew the little mounting buggers, put the sight on, then screw the mounting screws back on.

BTW, if you have the Samson folding front sight, you will need to call them and order a special sight pin. The 40L won't sight properly with the standard Samson post. This I learned in the field at an Appleseed.

[twyacht]

The 2 torx screws on the top rail "should" be torqued evenly. Have you tried taking the top rail off and dry mounting the sight?
I would take it off and try sliding the sight from front to back looking for tight spots.
Sorry to hear your getting a run around from Sig, I have had no such experience in the Cust Serv. area from them. If you can put a clamping style micrometer(preferably digital),  on the rail, if there is discrepancies in the width, etc,... take a picture of the numbers, and email it to them requesting a new top rail.

by Pathfinder,
BTW, if you have the Samson folding front sight, you will need to call them and order a special sight pin. The 40L won't sight properly with the standard Samson post. This I learned in the field at an Appleseed.

+1, Its more than a Sampson Post, its like the last couple inches of a folding flat-head screwdriver. Way Too Big!

Welcome, drahthaar. Getting 2? That's awesome. Get mags. Mine loves P-Mags.

FWIW terrylklun, even though I put a scope on mine, I use a micro drop of the "blue" loc-tite for all accessories, and torque evenly.

Keep us informed, and let us know how it works out. I love my Sig556.