Re: ? about ar15 barrel/upper bedding
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 2156SMK</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LongArm</div><div class="ubbcode-body">I know this is old but do you have any pics of the process? </div></div>
Not much to it.
Just degrease the barrel extension OD and the receiver ID, put a little sleeve retaining loctite in there and assemble it.
Wipe off any extra that comes out so it does not end up in the threads.
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This is pretty much what some of us old Dodge full time four wheel drive owners did with mid 70's "spindles". The bearings had a tendency to hammer out the seating surface in the spindle.
Solution? We'd degrease and sand the inside of the spindle, apply some devcon in a thin film, then put a good wax job on the bearing outer race and insert the assembly into the spindle. The end result was a zero clearance fit for the bearing and thus no more beating out of the bore.
For an AR upper, same process. Clean, sand with real fine wet/dry sandpaper just enough to remove any glaze, and apply a real thin skim coat of Devcon. Apply a good coat of wax (I like Kiwi Neutral) to the barrel extension and any surface that will contact the bore of he upper. Don't forget the threads of the upper and inside surfaces of the barrel nut. Assemble but don't torque. Just enough pressure on the barrel to make sure the Devcon is fully distributed, the barrel is in total contact with the upper, but not under any stress.
Let cure for 24 or more hours. Remove nut and barrel, clean up any Devcon that's migrated to unwanted areas. To remove the barrel easier, take a hardwood dowel that just fits inside the locking lugs on the extension and extends beyond the rear of the upper by 5"-6". Insert the dowel and give the end of it a few firm smacks with a hammer/mallet. Might be a good idea to make a collar of Duck Tape so when the barrel comes free the hammer doesn't hit the upper or your hand.
Once cured, the barrel and upper can be assembled and when the barrel nut torqued, no stresses induced in the nose of the upper. All the mismatched surfaces are now evened out with the skim of Devcon that's filled the voids. Really no difference in this than with a bolt action. It's all about stresses that are induced by action screws or barrel nuts.
