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Posted: 6/18/2012 5:31:55 PM EDT
Never built an upper before, so just wondering if this is normal or not.
I would imagine a tight fit here is a good thing, but that's as far as I can get the barrel into the upper by hand. Is this something that gets tapped with a mallet when there is s tight fit, or is something not right here? |
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With moly grease on the threads, good wrench and good fixture, you should be able to use the barrel nut to finish drawing in the barrel extension.
Back it off and verify that it is seated before starting the barrel installation. Disregard if there is a problem with pin/slot sizing.....pic is too fuzzy. |
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Quoted:
Quoted:
Thanks for the quick replies, just wanted to make sure everything was normal before I went whacking it with a mallet and damaging something. You don't have the whack anything if you use the barrel nut. Point taken, as of right now I do not yet have a barrel nut though. I'll wait until I do. |
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If the above doesn't work -
It should be tight due to the finish on the upper. If it is too tight due to an improperly sized pin slot in the upper, it'll need to be carefully milled out. Could do with a few light swipes of a jewelers file (1/1,000 in) on each inside flat. If you file or sandpaper it yourself, be extra careful, take very light passes and test fit often while being sure to remove from each side evenly as excess removal of one side over the other could cause sight alignment issues after assemble. |
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Lube the barrel extension or the interior of the upper. Lube the threads too. The barrel nut should suck the barrel properly in place.
When I was in the middle of my last build everyone was telling me to freeze the barrel (which doesn't harm anything to my knowledge), heat the receiver, lube and beat it on. That made no sense to me at all. I lubricated, pushed it in as far as I could (while properly aligned), tapped the barrel a little using a 2x4 as a buffer then used the barrel nut to push it the rest of the way. Worked perfectly, the barrel was fully seated and I had plenty of torque left to finish off the barrel nut (using a torque wrench). |
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