Picatinny mount not fiiting rail

[ewlyon]

Hey all,
So a while ago I mounted one of the brass stacker scout mounts on my mosin nagant. Installation was easy and the mount looks great, but today I tried to mount a scope to it and I found that the rail was about a millimeter or two too wide for the rings to slide on to it. I am hesitant to break out the file and make it fit so I thought I would come here and ask.
The mount is one of the nikon p-series and I previously had it installed on an ar-15 and it fit perfectly so i think the mount is not the problem.
I have not contacted brass stacker yet to see what they say.
Should I modify the rail so the mount fits or would I just be better off getting a pair of rings that dont have to slide on to to rail and then just tighten them down normally?

 

[JohnBT]

Is there a way to spread the rings using a longer screw or a spacer?

Your problem reminded me of BKL rimfire rings; they come with a hole just for spreading. The P-series are steel though, but you only need a mm. Got a vise and a pipe wrench?

 

[Outlaw Man]

It's not unheard of for a rail to be out of spec. I don't know anything about Brass Stacker's QC, but I agree the fact that you had the mounts on another rail points to the new rail being the issue.

Do you have a micrometer to measure the width of the rail?

 

[Walkalong]

The mount is one of the nikon p-series and I previously had it installed on an ar-15 and it fit perfectly so i think the mount is not the problem.

So mod the rail, get it replaced, or toss it and buy another product. But if you are willing to buy something else, no harm in trying to mod the rail. No loss if if doesn't work.

 

[ewlyon]

Thanks for the advice.Well I bought another mount that should fit since I know I was going to be needing another mount soon anyway, and that way I dont have to spread a ring set to only fit that rail. But before I do anything else I am going to contact brass stacker and see what they say.

 

[ewlyon]

Brass stacker responded very quickly and they were very helpful, offering to send out a new mount. Wonderful customer service. First I am going to measure the mount to see how far out of spec it is.