Please help an AR rookie

mississaugagunnut

mississaugagunnut

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So I joined the AR crowd this week and picked up a used Norinco 14.5" CQ-A. It has what appears to be a Spikes Free floating quadrail installed. There are Magpul MBUS installed as well.
When shooting, I had to adjust the rear sight for windage way over to the left just to hit paper at 50 yards. Once I did the groups were good. I believe the rail is not centered properly.
Is there a method to do this? The rail is fastened with 8 screws into a collar around the delta ring. There is a bit of play if I loosen all 8 screws. Any ideas?
 
If it's a spikes it'll be the BAR rail (or a SAR but that would be silly for a Norc, heck, even a BAR is)...there is an aluminum barrel nut that threads onto the upper receiver (thus no delta ring assy.) holding the barrel in place...however, there is a shim pack that comes with it so that the barrel is tight and the rail can be indexed properly. Those 8 screws are to be loctited into place during final assy. (Blue loctite...comes with the kit). There should be no play of the barrel (with the barrel nut properly torqued) and when the 8 screws are tightened (and loctited) there should be no play there also.
 
Thanks for the replies. The rail is not loose when the fasteners are tightened. There is a little wiggle room before they are snugged up all the way. I think that there is a shim kit that comes with the rail, I don't know if this was installed, I can't see any at the joint between the barrel and the receiver. Here are some photos.

This is the nut that the rail fastens to, I can't tell if there is a shim in there

P1000888.jpg


This is the rail installed

P1000878.jpg
 
Okay, I measured the barrel at the muzzle end in the quad rail and it is off to one side by about 1/8". That would cause the shift in impact that I am seeing. Now, how do I shim this thing so the barrel is centered?
 
To check if there's shims you'll need to remove the barrel nut (as the shims are placed on the inside shoulder threaded area). You might want to talk to Questar (they are the Spikes dealer) about getting the instructions/shims (I only have a hard copy). With your rail on and barrel 1/8" to the side...I'm gonna hazard a guess that your receiver is out of spec.
 
Thanks Brordo,
I have contacted Spikes about getting the installation manual and shims and they are being shipped. I hope the barrel is straight in the receiver and that it is just the quad rail that is a little tweaked. I think I will throw a scope on the railed part of the receiver and see how it shoots with that.
 
If you were able to zero the sights what's the problem? They're adjustable for a reason and its not for you to dial in windage for those long range shots.

TDC
 
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