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View Full Version : F Marked Front Sight On A A2 Upper???


m4forme
01-01-11, 08:41
I want to build a A2 middy but all the barrels have F marked front sight bases on them... Would there be any issues with setting zero on the elevation???
markm
01-01-11, 09:23
Possibly. You should have enough room to dial that Front Site Post down to get a good zero. You might struggle to get one of those homo 50 yard zeros, but with a middy, a good 100 yard zero should be possible.

Why not just run the carry handle? That's what I do.
m4forme
01-01-11, 10:20
sights but I just like the A1 & A2 style uppers... Guess I'm just old fashion...
Molon
01-01-11, 11:26
"F" Marked Front Sight Base


There is no difference in the overall height of an “F” marked front sight base and a standard front sight base. The only difference between the two front sight bases is the height of the sight “shelf” above the top of the barrel.


http://www.box.net/shared/static/uei1uar8kw.jpg



http://www.box.net/shared/static/2d520zm04w.jpg



The front sight post on a standard Colt front sight base will bottom-out in the sight well at approximately 24 clicks below flush. On an “F” marked front sight base the sight “shelf” is a whopping 0.040” higher than on a standard front sight base. That means you might have to turn your front sight post down approximately 6 clicks further with an “F” marked front sight base than on a standard front sight base. (6 whole clicks difference. Oh, the inhumanity!) So unless your front sight post is set at 18 clicks below flush with a standard front sight base, using an “F” marked front sight base will be a non-issue.





.....
markm
01-02-11, 10:03
There you go. About 6 more clicks. :cool:
usmcvet
01-02-11, 13:42
Nicely explained . I had pretty much the same question a while ago with the same answer. The photos in this thread and the detailed explination help make it clear.

I'm waiting on a 11.5" bbl from BCM should be here Monday. I'm going for the practical Retro with an A1 slick side upper. It is going to get a tritium FSP and a CSAT rear. A MOE handguards and light with no optic.
carbinero
01-03-11, 17:37
Possibly. You should have enough room to dial that Front Site Post down to get a good zero. You might struggle to get one of those homo 50 yard zeros, but with a middy, a good 100 yard zero should be possible...

Always good for a smile :D