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Posted: 10/10/2007 11:53:03 AM EDT
I just got a RRA 9mm upper. The bolt glides smoothly along its intended path in the upper just like all my other AR's.

When I mount my eotech on the rail and tighten the mounting screw, the bolt binds quite badly when moved along its normal path in the upper in the same area as the eotech mounting screw. Will this friction go away after brake-in?

Brian
Link Posted: 10/10/2007 12:19:15 PM EDT
You may want to ask Steve at RRA in the Industry section before taking a chance. Doesn't sound good.
Link Posted: 10/10/2007 12:26:25 PM EDT
Strange.

How much torque are you applying to the EOTech mount? I can’t imagine that little EOTech mount causing that much distortion to your receiver. Especially on the strongest part of the receiver!
Link Posted: 10/10/2007 2:11:21 PM EDT

Originally Posted By QUIB:
Strange.

How much torque are you applying to the EOTech mount? I can’t imagine that little EOTech mount causing that much distortion to your receiver. Especially on the strongest part of the receiver!


I am only using enough torque to hold the eotech stable. The bolt glides smoothly until it gets to the section right below the EOtech screw then the friction ramps up quite substantially.
Link Posted: 10/10/2007 2:21:30 PM EDT

Originally Posted By acidman:

Originally Posted By QUIB:
Strange.

How much torque are you applying to the EOTech mount? I can’t imagine that little EOTech mount causing that much distortion to your receiver. Especially on the strongest part of the receiver!


I am only using enough torque to hold the eotech stable. The bolt glides smoothly until it gets to the section right below the EOtech screw then the friction ramps up quite substantially.


This is just a standard 9mm flat top upper? Again, very strange. And first I’ve heard of this. I agree with contacting RRA. Can you post some pics?
Link Posted: 10/10/2007 3:59:06 PM EDT
Yes, it is a standard 9mm complete upper, NIB. I again lubed the heck out of the BCG and upper receiver and manually cycled the bolt probably 700+ times and it now runs much smoother. I am suspecting it was a manufacture variance concerning the tolerances and just needed some time to work smooth.

I will see how it runs when I get the magblock and magazines. I probably should have tried the above procedure before raising it as an issue on this forum. I have always been the type of individual to try to fix things myself rather then mail gear back to the company for a few tweaks.

Brian
Link Posted: 10/10/2007 4:10:54 PM EDT
If your positive that mounting the EOTech caused binding in the upper receiver and you could verify this with removal and installation, then I would make a call to RRA.

It’s still strange though because of how small the EOTech mount screw is, and the fact that the upper rail is probably the beefiest part of the receiver!
Link Posted: 10/10/2007 4:18:54 PM EDT
try the bolt with the lower removed.
Link Posted: 10/10/2007 6:36:31 PM EDT
[Last Edit: 10/11/2007 5:55:45 AM EDT by splitbolt]
That doesn't sound right about the EOTech. I'd verify if this is what's actually happening and contact RRA.

But, if anything is going to bind, I'd say it's your charging handle not your BCG.
How does it look after 700 manual cycles?
Try it without the BCG.
Try lubing the hell out of the charging handle and cycling. Big improvement?
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