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4/21/2015 2:06:32 PM EDT
I know this is not 100% the place to ask this but I figure the people here know more about this question so here goes:

Can a std height pinned FSB be used on a A4 flat upper and still retain proper sight alignment. I know there is a word for it but I forget. I ask this because I've bought a couple of new FN 20" barrels, date stamped 2010 and they both had std. FSB.

Thank you =)
4/21/2015 2:14:34 PM EDT
[#1]


Quoted:



I know this is not 100% the place to ask this but I figure the people here know more about this question so here goes:





Can a std height pinned FSB be used on a A4 flat upper and still retain proper sight alignment. I know there is a word for it but I forget. I ask this because I've bought a couple of new FN 20" barrels, date stamped 2010 and they both had std. FSB.





Thank you =)
View Quote
They should work fine.

 





If you have any issues zeroing, you can install a taller front sight post into the FSB. I had to do this with a 20" AWB era Colt barrel that I installed in a flattop receiver, and ran an A3 carry handle.







Colt and others sell the taller post.







SAW has them here: http://www.specializedarmament.com/products/Front_Sight_Post_9mm_SMG-221-289.html


 
4/21/2015 9:41:42 PM EDT
[#2]
Windham also has the +0.04 sight posts
4/22/2015 9:45:23 PM EDT
[#3]
Thank you both for your insight
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