Quoted:
Make your own cut-down low profile gas block, step by step:

First, I started with a FSB that I had to dremel into to get the pins out.  It was otherwise ruined, so I figured, why not cut it down???




Get a dremel and a cut-off tool, and start whacking the top off.  I didnt even burn up one disc for the whole project!




First step complete:




Now cut off the sling mount and bayo lug, if desired:




Here is what she looks like at this point.  Ugly!




The rest will be done with a sanding drum.... or you can use a griding stone.  I find the drums, while they burn up quick, go a little faster:




Most of the rough work is done.  At this point, just smooth it up a bit to look better:




If you are going to mount your FSB back on the same barrel it came off of.... then re-use your taper pins.  If you are going to mount the FSB on a different barrel, you will need to drill and tap for set screws to hold it to the barrel.  I then drilled with a #21 drill, and tapped with a 10-32 tap.  I also had to taper-grind my set screws.... so they were more "pointy" on the front.  Without doing this, they would bottom out against the barrel with hardly any threads, and would strip out.  Dont get them too tight or they will trip.  Use red-loctite on them so they wont back off.




A quick coat with flat black spray paint:




Finished product:

Quoted:
3/4 of the way down on this page
http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782