Just got a barrel assy for a build and the gas tube hole in the FSB seems slightly too small for the gas tube. Any reason I shouldn't just use a Dremel and open it up a little bit?

Thx.

Whisky19

maybe just dirty or has burs.


get something to clean it out first.

The Bushmaster barrels I've used were a little tight unless the FSB hole was first cleaned with some sort of cleaner or penetrating oil and a Q-tip.  Try some Hoppes or break-free on a Q-tip, run it in the hole, swab with dry end of Q-tip, and then insert gas tube.  Might find it fits a little better.

Quoted: Any reason I shouldn't just use a Dremel and open it up a little bit?

Yes.  Gas leak/blow-by resulting in bolt-overs, FTEs, and short-cycling in general.  If you absolutely have to enlarge the hole, use fine grit sandpaper rolled into a tube and work it by hand.  It's supposed to be tight.

Thanks guys,

Glad I asked before just going at it with the Dremel.

ETA: Got it in! I got myself some emery cloth at Home Depot and slowly worked the fsb hole with it rolled up in a tube as suggested. I also polished the tube using the emery cloth. I just kept at it until the tube almost slid in. I then lightly tapped the tube in using a plastic hammer and it slid right in. Using a pair of pliers, I twisted the tube back and forth in the hole and it now fits fine, Thanks for the help!

Whisky19






Whisky19