Just out of curiosity, what were you using for the install? Reaction Rod, BEV or a clam shell type receiver block?
Just out of curiosity, what were you using for the install? Reaction Rod, BEV or a clam shell type receiver block?
I used a DPMS upper receiver fixture, as that is what Mega recommends in their instructions for their Maten uppers. I had a clamshell style fixture years ago, but I found it was rather flimsy. I may invest in a reaction rod in the future, but I'm kind of done building rifles for a while.
I've used a clamshell for years never found it to be an issue that caused sights to be out of whack. Same for using barrel blocks when installing and removing muzzle devices. Any time they were skewed, it was due to the pinned fsb, or oos upper.
Last edited by misfit47; 05-19-18 at 23:22.
Ive also had no issue with the clam shell type but the reason I brought that up is I have seen the reaction rod type twist the upper especially if they require more torque to get the barrel nut and gas tube hole aligned. From the few I have looked at it appears to put too much pressure on the indexing pin and either stretches the slot on the upper or twists the upper at the threads and causes the sights to zero to the extreme right.
I got my upper back from Colt today, and as far as I can tell the front sight was canted. I unpacked my upper from the box they sent it in, and found an invoice which simply stated front sight canted. No other notes or explanation was provided. I called Colt customer service for more details, as I wanted to know if they adjusted the front sight base, or replaced the barrel assembly. The phone rep stated that he could not address my questions, as they do not have a way to track the gunsmiths notes electronically. To get an answer, he would have to walk back to the shop and ask in person. However, he stated he couldn't do that at the moment, as he was the only person answering phones at the time. He offered to talk to the gunsmiths Monday morning before his shift, and call me back once he found out anything. So as far as I can tell it was a canted from sight base, but as to what was done to fix it, I don't know.
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