I have a 2008 vintage JS prefix 556 with a canted top rail and I'm hoping to find a fix for this. It is canted down to the right looking at it while shouldering the rifle. I was thinking maybe taking off the rail and milling a few thousand off the opposite side (sort of tappering the bottom from left to right) but not sure if that will work. Also thought about shimming the right side but was looking for a more permanent solution.

Any suggestions would be appreciated.

Thanks,
Hojo

My first 556 had the same issue. I sent it to Sig, they milled to opposite side of the top rail to true it on top of the caddywampus upper receiver. I was sending it off to have a Swiss steel optic rail on the receiver, so it needed to be true. I put the upper in a vice using wood blocks, ensured the top of the trunion was true with a machinist level, then very carefully used a large flat punch to true the canted portion of the receiver. Mine was basically all at the rear. I took my time, went slowly, and checked/rechecked frequently. It turned out great.

I gave Sig a call and they said to send it in, cost 27.50 for the shipping. They said it has a lifetime warranty, also asked them to replace the torn rubber dust covers where the c/h slides.

Just have to wait and see.

What's the number you called?

603-610-3000
I believe it is option 1 then option 1 again.

I spoke with Brian and Paul. They said it had a lifetime warranty but I had to pay for shipping. Gave them a credit card over the phone for $27.50 and in about 15 minutes I had an email with a shipping label and instructions. They use FedEx, and they pick up at my work so it went pretty well.

Shipped it Monday and they got ot this morning, so now I have to wait and see what happens.

Thanks.

Keep us posted.

I picked up my Sig this morning as they tried to deliver it on Friday but no one was home to sign for it. Never got an email. I called sig to find out what was done and customer service could not say other than they fixed the rail, and the paperwork with the rifle would say. Well all it said was that they did fix it. I also asked them to fix the looseness between the upper and the lower, they shortened the front pivot pin and stuck in an accu-wedge. The last item I asked them to fix was the rubber dust covers as mine were torn, that was not done.

I noticed on Friday that there was a pending charge for $1.00 on my bank account and could not not find a charge for shipping, I looked again today and that was gone as well.

It would have been nice to here from them prior to shipping but at least the rail got fixed.

Can you tell how it was fixed, if they milled one side...etc?