vingrjoe
8 October 2010, 13:46
I just recently assembled two seperate uppers. Both have Bushmaster 20" Govt. Profile barrels, one upper has a YHM A2 receiver and the other has a YHM A3 receiver. It took me about 69 ft lbs of torques on the A2 and about 62 ft lbs of torque on the A3 to get the barrel nut timed for the gas tube.
I took them to the range to zero the sights using the 25m targets found online. My A2 took 14 clicks to the left for windage and my A3 took 16 clicks to the left for windage. I am not happy with having that many clicks either way for windage. I suspect my FSB possibly were canted due to the torque being on the higher end. I used the Bushmaster clamshell receiver block when installing both barrels.
I was looking for some advice on this matter.
- Would lapping the end of the receivers where they mate up to the barrel collar help me to get the nut timed in at a lower torque ?
- Also, would lapping assist in reducing the amount of adjustment in windage and elevation to zero my rifles ?
- Is there any disadavantages to lapping my upper receiver ?
-Should I use barrel vise blocks like in the TM instead of the clamshel receiver block ?
-Or should I use barrel vise blocks in conjuction with the clamshell receiver block to secure the barrel when tightening ?
Thank you in advance, I look forward to any recommendations.
I took them to the range to zero the sights using the 25m targets found online. My A2 took 14 clicks to the left for windage and my A3 took 16 clicks to the left for windage. I am not happy with having that many clicks either way for windage. I suspect my FSB possibly were canted due to the torque being on the higher end. I used the Bushmaster clamshell receiver block when installing both barrels.
I was looking for some advice on this matter.
- Would lapping the end of the receivers where they mate up to the barrel collar help me to get the nut timed in at a lower torque ?
- Also, would lapping assist in reducing the amount of adjustment in windage and elevation to zero my rifles ?
- Is there any disadavantages to lapping my upper receiver ?
-Should I use barrel vise blocks like in the TM instead of the clamshel receiver block ?
-Or should I use barrel vise blocks in conjuction with the clamshell receiver block to secure the barrel when tightening ?
Thank you in advance, I look forward to any recommendations.