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Posted: 6/15/2014 12:04:28 PM EDT
| Removed the barrel from my DPMS LR-308 only to find that it was hand tight from the factory. Under nominal torque the forearm is no longer timed to the lower and the attached rails are out of position. Try as I may I can not find a source for ar-10 forearm timing shims. ID 1.200 OD 1.365 Thickness 0.001 or 0.002. Any known sources? Thanks in advance! |
| The forearm is attached to the barrel nut. The barrel nut is over-rotated once the correct torque is applied. To fix this a shim washer is stacked onto the barrel nut to reduce the nuts rotation. It should take about 0.003 inches of washer to remove "one hole" of rotation. That should bring the picatinny rail back under the barrel. |
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Not sure if they are even still in business, but this may help:
Ar10Barrels.com The link to the shim pic is broken. But the contact link at the bottom of the page works. |
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Quoted:
Take it off the face of the receiver. A flat marble/glass plate and some 600 grit automotive paper will get it done. I was going to suggest this, but realized it would make the timing worse. He would have to take of enough for almost a complete rotation. |
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Quoted:
Bison may have them in a couple of months. Other lead didn't pan out. Still open to ideas...... Thanks so far! You can make a shim that will work and will not be able to see it. Get a soda can and use a hole saw. Cut the inner diameter first and then the outer. |
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