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Posted: 10/19/2013 2:57:36 PM EDT
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First time build so forgive my lack of experience.....so I get the BCG all lubed up and insert it along with the charging handle and what I'm finding is the bolt isn't perfectly aligned with the grooves in the breach of the barrel so the bolt won't go in and seal the breach. I realize the bolt should sort slide in-and-out of the bcg to adjust vary the location of the bolt presumably so it seals the breach. Although it moves freely when out of the upper, when you place it in the upper, the bolt has to be extender out fully otherwise the cam pin conflicts with the opening to the upper where the BCG slides in. When the bolt sits against the breach of the barrel, the grooves should be twisted maybe 15 degrees so they mesh but I don't want to push too hard for fear of damaging something.
Here's a pic of the breach of the barrel from the underside of the upper, and then the bcg inserted: http://www.perfectswitch.com/images/barrel.jpg http://www.perfectswitch.com/images/barrel2.jpg http://www.perfectswitch.com/images/barrel3.jpg |
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Quoted:
give the BCG a push while in the upper reciever, not gonna hurt anything unless u get the sledge hammer out, when the bolt moves in the BCG it also rotates slightly You obviously did not look at the pictures. You might rethink that advice. The barrel extension is installed improperly or defective, as it is not lined up with the upper receiver. |
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You did line up the little placement pin on the barrel extension with the channel in the upper receiver? If that's the case it looks like your barrel extension was not done correctly. Where did you get the barrel? ETA this has nothing to do with your BCG... ^this, looks like in the picture the barrel lower slots are not centered |
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Take the barrel off and you may find the locater pin sheared or it is not installed at the 12 o'clock position. That's also good advice - I have had them fall out before. It is possible during torque they can come out or shear. However, this would be readily apparent by looking at the gas port as well. OP - here is a barrel properly installed (also a JP barrel) 
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I gave it some wraps with it doesn't seem like it wants to rotate and again, I'm hesitant to hit it too hard cause I don't want to screw up a new bolt/barrel assembly. Again, stop "wraping", it is NOT the BCG; and no amount of force will make it rotate! Take the barrel nut OFF and verify that the pin is in the correct spot. And then take more pictures. Email JP the pictures and get a return shipping label. |
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Okay guys, I took it apart and you're right, it must have twisted slightly because when I put it back together....everything aligns. Appreciate the assistance. sorry, that doesn't pass the smell test. it cannot rotate like that without more to the story than you are sharing. 
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Took it apart and the barrel must not have been seated where the 12:00 "key" sits and when I tightened the barrel nut, barrel was slight off center. When I put it back together and insured in was keyed correctly, all lined up. Rookie mistake.
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sorry, that doesn't pass the smell test. it cannot rotate like that without more to the story than you are sharing. Quoted:
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Okay guys, I took it apart and you're right, it must have twisted slightly because when I put it back together....everything aligns. Appreciate the assistance. sorry, that doesn't pass the smell test. it cannot rotate like that without more to the story than you are sharing. |
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Took it apart and the barrel must not have been seated where the 12:00 "key" sits and when I tightened the barrel nut, barrel was slight off center. When I put it back together and insured in was keyed correctly, all lined up. Rookie mistake. Quoted:
Took it apart and the barrel must not have been seated where the 12:00 "key" sits and when I tightened the barrel nut, barrel was slight off center. When I put it back together and insured in was keyed correctly, all lined up. Rookie mistake. Quoted:
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Okay guys, I took it apart and you're right, it must have twisted slightly because when I put it back together....everything aligns. Appreciate the assistance. sorry, that doesn't pass the smell test. it cannot rotate like that without more to the story than you are sharing. Ok, looking at the pics again you can see the barrel isn't fully inserted, so that makes sense. It mas misleading I guess that you were sure it was inserted properly to begin with. Good you figured it out. |
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Ok, looking at the pics again you can see the barrel isn't fully inserted, so that makes sense. It mas misleading I guess that you were sure it was inserted properly to begin with. Good you figured it out. Quoted:
Quoted:
Took it apart and the barrel must not have been seated where the 12:00 "key" sits and when I tightened the barrel nut, barrel was slight off center. When I put it back together and insured in was keyed correctly, all lined up. Rookie mistake. Quoted:
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Okay guys, I took it apart and you're right, it must have twisted slightly because when I put it back together....everything aligns. Appreciate the assistance. sorry, that doesn't pass the smell test. it cannot rotate like that without more to the story than you are sharing. Ok, looking at the pics again you can see the barrel isn't fully inserted, so that makes sense. It mas misleading I guess that you were sure it was inserted properly to begin with. Good you figured it out. Agree, that was confusing. I will give OP benefit of the doubt and assume he had difficulty pressing the delta ring and turning the nut at the same time, so it probably got twisted a little on him while he was turning it down. |
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OP, it would be beneficial if you learned the proper nomenclature of the AR platform, and how it works. First, the bolt has to be extended to go into the upper. That's how it works! What you refer to as the Breech is the barrel extension. And the bolt doesn't seal the chamber. Anyway, glad you found and corrected your problem. |
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Working on the vocab and yes, I'm glad I was able to figure out my error.
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OP, it would be beneficial if you learned the proper nomenclature of the AR platform, and how it works. First, the bolt has to be extended to go into the upper. That's how it works! What you refer to as the Breech is the barrel extension. And the bolt doesn't seal the chamber. Anyway, glad you found and corrected your problem. |
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