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Posted: 8/4/2016 9:08:34 AM EDT
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Hello, looking for help on aligning the upper/barrel with my handgaurd. Im using an standard Andersen reciever, with Aero B.A.R. barrel nut and Aero hand guard. I understand perfection is near impossible with free float handrails, but not happy with my outcome. Ive contacted both Andersen and Aero with little to show for at this point.
Any ideas/advice welcome. Thanks  " />
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Really need to have the upper in hand to resolve the problem.
Hence could be that the face or even socket of the upper receiver barrel extension socket is not square to the center line of the upper receiver, and it needs to be corrected. The barrel extension not square to the center line of the barrel bore, of the barrel bent, The barrel nut mating surface to the upper receiver socket face is not square to its OD, or you have something between the two that is causing the cant of the barrel nut retaining the tube. The barrel nut's OD and bolts for the tube not square to center line of the receiver. Or, you cant bent the upper receiver barrel socket by tightening the barrel nut incorrectly instead. Hence if just a install problem with crap between the barrel nut to upper socket face that has to be cleaned to get the barrel nut to seat square, could be a easy solve. If not, then we go down the rabbit hole of first making sure that the upper receiver barrel socket is square to the center line of the barrel/ get it back to square if the barrel nut was over torque. 
Upper barrel socket squared (both socket and face of mating lip), 
From here, we put the barrel between centers with a dog leg on the lathe to check for run out in the barrel to make sure is not bent, then focus on the barrel extension surface and flange to make sure they are square to the bore line, and if not too bad being out of square, a few light cuts to bring them back in to square. Note, C6 cutting insert goes through HSS like hot butter. With barrel, barrel extension, and upper squared, then we focus on the barrel nut to make sure its mating surface to the upper socket flange is square to the barrel nuts OD/it's mounting bolt channels square and parallel to each other (correct if possible), then check the tube to make sure it mating surface/bolting channels are square and parallel to the OD of the tube, and to make sure that the extruded tube is not bent as well. Hence some times parts are plug and play with everything coming nicely together, and other times the are not. When not, you either have the tool and talent to correct the problem, or you start sending parts back that are out of spec to be replaced isntead. |
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thankls for the reply dano will be taking it apart again this weekend, and will be looking things over.
How dose one check this to make sure the upper receiver barrel socket is square to the center line of the barrel. And then get it back to square if the barrel nut was over torque? |
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As you can see is in the photo I posted.
I have a Mandel that I grease and press fit into the upper receiver that will first square the upper receiver barrel socket with the center channel in the upper receiver (when someone over torques a barrel nut to slightly bend the upper receiver barrel socket itself), then the whole receiver is placed in a lathe to true up the front edge of the barrel socket next (to square the works with the upper receiver channel/center line). For barrel work, I have a live center that will fit inside the barrel extension to contact the front of the chamber, and use the live center show in the above photo for light pressure against the muzzle crown to just dial gauge indicate parts. If I need to do any cutting or straighten type work, then the I have a 1/2x28 threaded piece that I install on the muzzle threads so I can either use a live center off or roller steady rest off it, so the muzzle crown is not distorted by any cutting pressure against the barrel. Note, half the time when I have a barrel in the lathe, not really happy with the crap crown it has to begin with, and will end up just re-crowning the muzzle anyways isntead (if the barrel bore is not chrome lined). Hence the crown is the edge metal between the face of the muzzle and the rifling bore, and on some production barrels, the crown is cut with a cutter that can end up with the crown not concentric to the bore, or just too deep instead. 
Total shite crown work, 
No crown relief edge at all, 
More of an ideal crown edge instead. 
Hence the face of the muzzle is cut to a 11% angle, then a brass angle plug with a hint of lapping compound is feed square into the muzzle bore to just lightly crown the muzzle for a slight relief of the square edge of the two surfaces. |
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OMG. Does that shoot around corners? |
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Quoted:
Hello, looking for help on aligning the upper/barrel with my handgaurd. Im using an standard Andersen reciever, with Aero B.A.R. barrel nut and Aero hand guard. I understand perfection is near impossible with free float handrails, but not happy with my outcome. Ive contacted both Andersen and Aero with little to show for at this point. Any ideas/advice welcome. Thanks I would use the Brownells lapping tool and square up the face of the receiver. lapping tool This is the Anderson upper receiver I used on my last build after being squared up with the brownells tool, it took me less than 5 minutes to square it up:  " />
Gary |
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Couldnt loosen the nut with a barrel nut wrench, and didnt have a cheater bar or breaker bar available. My question is at this point does it make since to live with the hand guard issue as the barrel nut is aparently seated. Or disasemble, re thread the reciever and get new barrel nut ect.
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