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Posted: 1/2/2016 1:01:26 PM EDT
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Ok so this might be a dumb question, but the jam nut that came with my handguard, is that tightened to put pressure on the quad rail, or tha receiver? I only ask because the handguard has a locking bolt on the bottom, so the jam nut would be redundant.
I may be WAY over thinking this |
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your top-rail section needs to fully align with the top rail of the receiver (obviously, i'm sure you knew that) .... but you also need proper torque on the barrel nut, and alignment for your gas tube (Again, obvious)
The jamb nut comes into play because with proper torque and gas tube alignment you do not always end up with the treads perfect to get the necessary rail alignment. The process works like this: 1) torque barrel nut to with in specified range 2) align gas tube (my require adjustment of barrel nut) 3) screw on hand-guard and align top rail as closely as possible. 4) snug jamb nut to hand-guard to ensure it stays put 5) tighten the locking bolt to make sure the hand guard stays put There's value in redundancy -- one is none, two is one. |
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Quoted:
your top-rail section needs to fully align with the top rail of the receiver (obviously, i'm sure you knew that) .... but you also need proper torque on the barrel nut, and alignment for your gas tube (Again, obvious) The jamb nut comes into play because with proper torque and gas tube alignment you do not always end up with the treads perfect to get the necessary rail alignment. The process works like this: 1) torque barrel nut to with in specified range 2) align gas tube (my require adjustment of barrel nut) 3) screw on hand-guard and align top rail as closely as possible. 4) snug jamb nut to hand-guard to ensure it stays put 5) tighten the locking bolt to make sure the hand guard stays put There's value in redundancy -- one is none, two is one. This is correct OP. You may not have a lock bolt so #5 may not apply. |
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This. Its purpose is to keep the handguard tightly fastened to the barrel nut once you screw the handguard onto the barrel nut. Quoted:
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The jam nut is tightened against the handguard This. Its purpose is to keep the handguard tightly fastened to the barrel nut once you screw the handguard onto the barrel nut. This ^ I find it easiest to have the jamb nut touch the rail when the rail still needs to be turned about 1/8th turn... then turn the rail to snug it to the jamb nut and align the top rail. Takes a couple times to find the right starting place for the top rail to align. Never found a wrench to fit those jamb nuts. If someone has a better way I'm all ears... |
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