What is the correct size screw for the side rail on an MSR STG 556 3rd gen, the screws that go in the bosses that mount the side rail.


Thanks everyone,
Sean

M6 course?

I think it's something like 1/4-20. It's been a while since I bought mine but I'll check my PMs to see if the answer is still there...

I could not make the 1/4 x 20 without alot of force. I was worried about galling the threads. If I can get some conceses here I guess ill go get some...

Anyone else agree on the M6 course or the 1/4 x 20?

Sean

I had a concern also when I attached my side rail to my Gen 3 receiver. Their seemed to be a lot more resistance than what I thought there should be. They did go in though. The rail screws are 1/4x20/3/8. I bought a 6" and a 9" rail for my Gen 3 last year (factory MSAR) I attached the 9" rail to the receiver. I actually forgot that I had the 6" rail still  and asked here if anyone knew what the screw size was. The 1/4x20/3/8 is the same for the receiver and the E4 stock. I put 1/4x20x1/4 in the empty screw holes of the E4 stock just for aesthetics.

Pretty sure Dave sent me some 1/4x20 screws to put into mine.  They were kinda hard to get in.



Make sure you get short ones so you don't mess up the moving bits.

Thanks Everyone 1/4 x 20 it is!