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12/18/2008 8:22:57 AM EDT
Hey fellas, Anyone got any tips and/or tricks on drilling a blank FSB. I have a DPMS barrel which has a gas block on it. I want to add a FSB to be able to co-witness with iron sights through my red dot. I've some looking into it, and I'm gonna have to custom drill it. I know it uses tapered pins, and I am a shade tree machinist. Just wanting to know if any of you have done this. Any info would help. Thanks in advance.
12/18/2008 12:24:35 PM EDT
[#1]
Taper pins were used because it is a cheap, mass-produced solution.  To do it in the home shop requires a solid drill press and taper reamer.

A better solution which is every bit as strong is to drill it #29 drill, then use this to hold a 1/8" end mill and cut small flats on the barrel.  Tap the FSB for #8-36 dog point setscrews in 4 places. Now the FSB can be indexed for precise centering of the rear sight.  Use a wicking thread locking compound on the screws after final zero.

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