Tuesday, October 15, 2013

AR adjustments

So... the barrel of an AR (at least my AR) has a shoulder about 9/32nd of an inch from the center of the gas port.  and that's the same distance with the sight block port.  Maybe when tightening everything down the sight block crept forward a bit and that was why it only shooting semi.

I reassembled, paying close attention I didn't knock the sight any, and wanted to hit Hap Baker with Saucy Trollop, to test.  You gotta get there more than 10 minutes early if you want a lane anywhere.  Maybe next weekend.

If it doesn't cycle then, then I will have to go back to the drawing board.


Hat Trick said...

Try blowing compressed air in the barrel with the ends plugged and see if you get air out the gas tube.

Geodkyt said...

If you're setting it up for a free float tube, remember that you will be missing hardware (the handguard cap) between the gas block and the shoulder -- that space is designed to take that piece into account, with some tolerance.

BEST solution is to shim with washers (which you may well have to create yourself to get the right dims) and just leave them there after installation. Second best is make sure you have the right offset, and set feeler gauges to that space so you han go hard on when tightening teh block. Then remove feeler gauges.