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Posted: 6/9/2011 12:52:03 PM EDT
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Does anyone know who sells a fsb that is compatible with an A2 style upper? I'm in the market for a new barrel and I also need a compatible fsb. I have read that the f marked fsb isn't compatible. Is this true?
Thanks... |
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the F base is slightly taller. when you raise the front sight you lower the point of impact. you may run out of down adjustment with the front sight post when trying to correct the point of impact back to where you want it. so, non-F are better for A2 and F is better for flattop. You can find Colt, FN, Bushmaster, DPMS, RRA, Double Star that all sell/ or made the non-F base barrels. if you just want the FSB Brownells or Double Star sell them.
advntrjnky |
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I have an A2 upper with an F marked FSB on a 20 inch barrel.
I had to adjust the rear sight 6 clicks up by loosing the little rear sight screw with a 1/16 allen wrench, as outlined in this thread, http://www.ar15.com/forums/topic.html?b=3&f=18&t=328143 It's still set at the 8/3 position but is now 6 clicks above bottoming out. I still have to crank the front sight post way down in it's housing, but I can get a good 300 yard zero and still have about 5 clicks lower of front sight adjustment left. (That's actually shooting the 300 yards, not some 25 yard zero crap). That's with the rear elevation set at 8/3, but 6 clicks above bottoming out. That gives me plenty of elevation adjustment for 300+ range if I ever shoot that far. An A2 upper will work with a F marked FSB, but you have to make some adjustments, and your front sight post will set really low in it's housing. I hope all that makes sense? |
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Take it to the range and shoot for effect before you do anything. Let us know how YOUR rifle shoots as set up
This! I've had quite a few AR's and for me the FSB thing has never been a problem with rifles or carbines getting them sighted in at various distances flat top or fixed with a wide variety of sights. Guess I'm just lucky but if a problem did occur I could also probably fix it pretty quick with something I have laying around. |
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