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Posted: 2/24/2017 1:49:14 PM EDT
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While I'm not new to AR's I'm a newbie when it comes to building one. I bought a PTAC upper and a PSA lower kit for a truck gun and I'm having an issue with cycling. There are times when the bolt doesn't go into full battery, when it happens I eject that shell and maybe the next one and it will engage. Both my Colt and my S&W worked flawlessly from day one so this is something that I haven't experienced before. I know some tolerances are very tight but even using the forward assist it doesn't go into battery. Anyone have ideas for me to check?
Thanks TonyG |
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Remove the bolt carrier assembly and charging handle. Visually look at the gas tube, does it look centered in the charging handle track, or is it canted off to one side? Next try inserting just the bolt carrier (No Bolt, Cam, or Firing Pin) into the upper receiver, and slide it forward, what you are looking for is that the bolt carrier should slide inside the upper receiver with no resistance, and go all the way forward and mate with the gas tube with no resistance. If you get resistance when dry fitting the bolt carrier, then you may have something that is out of spec for tolerance, misaligned barrel nut that is cause the gas tube to be out of alignment with the bolt carrier key (gas key), badly machined bolt carrier key (gas key), or something else. If it is bad machining, or the barrel nut is misaligned, then I would contact the manufacturer and get them to fix or replace it.
CY6 Greg Sullivan "Sully" SLR15 Rifles TheDefensiveEdge.com (763) 712-0123 |
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