Colt 6920, geissele mk8 rail install, barrel not centered.

[Dirknar]

New Colt 6920, I shaved down the fsb, and installed a new mk8. The barrel is not centered inside of rail. It's approx 1/2 a millimeter off. I took a straight edge to the rail and upper, it seams dead on, both sides. I'm thinking it must be the receiver face.

Is this fairly common? Should I buy a facing tool?

[scooter22]

Doesn't matter. Get to the range and zero it.

[Dirknar]

Ok will do. Just annoying? What about iron sights mounted on the rail? The pic makes it look better than it looks with naked eye. You can tell its crooked. (Kinda like hillary,bam! )

[GACS]

Dirknar,

Shoot us a few more pictures at sales@geissele.com along with some more information about the upper. If there is an issue with the rail, we will get you squared away.

-Geissele Customer Service

[Dirknar]

Wow! That's customer care,right there! I bought a geissele ssa trigger for it too! Glad I did!

[ggammell]

Ok will do. Just annoying? What about iron sights mounted on the rail? The pic makes it look better than it looks with naked eye. You can tell its crooked. (Kinda like hillary,bam! )

This is why you have adjustable sights.

[GH41]

1/2 mm = almost .020 so you are .010 off center. If it bothers you that much give the rail a whack with a rubber mallet. If you don't have a rubber mallet just slap it against the nearest tree.

[Dirknar]

I hear you, but the rail is straight. It's the barrel that's crooked. Here's a better pic of how obvious it is.


And here's a pic of a straight edge. It is dead straight all the way down both sides of the rail and receiver, with optic removed as well.

[Dirknar]

I know there is some knowledgeable people on this forum. you guys say, no biggie, shoot it, then that's what I'll do.

I might buy that receiver lapping tool in the future though, it seems cheap enough and couldn't hurt in a quality build.

[GH41]

A measurement with a pocket ruler and a rusty framing square isn't enough to convince me something is off. You are wrong about the lapping tool doing no harm. Think about how it is used. How can it work? A lot of tools in the Brownell's catalog remind me of stuff in the J. C. Whitney catalog. If I order 5 things that increase my HP 20% I can double my motor's HP. I don't think so.