F Marked Front Sight On A A2 Upper???

[m4forme]

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]

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]

sights but I just like the A1 & A2 style uppers... Guess I'm just old fashion...

[Molon]

"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.










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.





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[markm]

There you go. About 6 more clicks.

[usmcvet]

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]

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