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Posted: 3/11/2007 1:15:57 PM EDT
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I have a question for the AR gurus here. I am assembling a new upper for my AR and I am replacing the front sight base with a DPMS gas block. I have two questions pertaining to this. I have checked out other threads here on AR15.com and am pretty sure I got a handle on #2 but would still appreciate any other input from the folks here. Question #1 How do you know for sure that the gas block is lined up correctly with the gas hole in the barrel? Are there any tips to ensure correct placement? Question #2 How do you ensure that the gas block/front sight is lined up correctly with the upper receiver/rear sight? You know, how do you make sure everything is straight? Thanks for the help in advance. EDIT** What is the best source for peel washers to index a YHM 5c2? Thanks again ** |
#1 measure from the shoulder of the barrel step down to the hole, then measure from the end of the gas block to the hole in the gas block and you will get close, remember to allow a small space between the gas block and the step up in the barrel. some things I have done is put the gas block on for a test fit and tape up one end of the barrel then shoot some air down it with the air compressor and listen for the most air passing through the gas block if all else fails use trial and error, shoot a couple of rounds and see if it cycles. adjust the block if it doesn't #2 if you have a railed upper I have used a couple of back up front sights and looked down the sight line. or run some small diameter fishing line to line up the two front sights to the rear sight. crude, but it worked for me. |
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