Pistol Buffer question

[killmime1234]

also a little thing to remember the hole is drilled in the standard location

if you take your gas block and press it right up to the barrel shoulder it may close off a bit since it is expecting the handguard retainer gap

As Randall stated about the size of the holes, the gas hole in most gas blocks is around .150" in diameter. The gas hole of all the 7.5" barrels I've come across has been .0625" in diameter. So, basically, the gas block would have to be .0875" out of alignment before it started to restrict gas flow. Most handguard caps are more like .040" thick so, against the shoulder or against a cap, it shouldn't matter.

[ar15barrels]

As Randall stated about the size of the holes, the gas hole in most gas blocks is around .150" in diameter. The gas hole of all the 7.5" barrels I've come across has been .0625" in diameter. So, basically, the gas block would have to be .0875" out of alignment before it started to restrict gas flow. Most handguard caps are more like .040" thick so, against the shoulder or against a cap, it shouldn't matter.

To further refine your numbers, gas passage in Front sight bases is usually 0.156", Gas ports run from 0.050" to 0.110" (across ALL DI AR variants) and handguard caps are typically 0.025" thick.

[shinbone1]

If it's a set screw type gas block, it may have come loose and shifted away from the gas port. That can happen if the screws aren't tight enough, don't have loctite, aren't knurled-tip, etc.

This might be the case with a clamp-on type as well, but I haven't witnessed it nearly as often.

This was the issue. A friend of mine found it this morning after tearing it down. Thanks everyone.

[shinbone1]

Sorry, even though the issue has been remedied here's some backgroud for those subscribed.
The lower was assembled by me from an 80% and functioned fine. The upper was purchased on here from a seller with a good rating. He assured me that the upper functioned flawlessly when he shipped it. I, assuming this was accurate and knowing next to nothing about AR pistols, (aside from that they can be tempermental) just took it to the range and tried to fire it. My friend called me this afternoon and said he has it running like a swiss watch.

Here is a link to the upper for those still interested. He didn't have any info on the barrel maker.

http://www.calguns.net/calgunforum/showthread.php?t=971076

[ar15barrels]

This was the issue. A friend of mine found it this morning after tearing it down.

The easiest fix for this is a detent drilled on the barrel 180 degrees from the gas port.



Then, when you reassemble, drop the rear setscrew into the detent before tightening the other setscrews on the gas block.

[shinbone1]

Thanks for the tip. I plan to switch out the gas block at some point so I'll give this a try.