picatinny rail slightly narrow..out of spec?

[Greggxr750]

Hello, everyone, thank you for reading my first post. I am excited to take my 15-22 to the range for the first time. My local dealer did not have the MOE version so I just started to swap out parts on my own. I just installed the mbus gen sights and sadly, they are not sliding on the rail tightly. I cannot get the screw to tighten and secure these sights down like I can on my ar15. Is it possible that my rails were just made slightly out of spec? Any thoughts on this would be greatly appreciated. Thank you.

 

[SimpleWeaponSolutions]

That is odd. If you had not tried it on the your AR15 without issue I would say that the sight is either out of spec or a knockoff. If you have a dial caliper I would take measurements from both rails to compare dimensions, or you may want to head down the LGS you bought it from and see if you can try out a few other items that mount the rail to see if they work.

Worst case scenario is that you will have to send it in to S&W for inspection.

 

[Greggxr750]

the sight does fit on the ar15 perfectly, and I took off the mbus from the ar15 to try on the 15-22 and it's the same. I don't have a caliper but it's pretty clear to me that it is just a tad narrower. that's strange to me.

 

[glg20]

I recently picked up a 15-22 MOE and the sights fit fine. They are the gen II sights. I have no idea if that makes a difference.

 

[ESW]

All of my 15-22 rails are slightly smaller, than my AR-15 rail. Some parts don't tighten as well as on Mil Spec picatinny. I replaced my quad rail so now I'm good.

 

[sound wave]

have to edit what i said. i thought my magnifier was loose on the 15-22 compared to the AR. i double checked it and it clamps tightly to the 15-22. the part that was moving was the hinge of the flip away section. oops

so, the width of my AR and 15-22 are the same as far as i can tell.

 

[Gopher Slayer]

You'll have to put a little more muscle into it to get it to securely clamp to the 15-22's rail. Make sure you have the correct size screwdriver/bit (no slop).