AR Sponsor
Posted: 11/25/2007 4:20:36 PM EDT
|
I've been wondering what everyone was talking about when I read about "F" marked FSB and recently, through some reading on here, I now realize there is a difference in the F marked and I guess just a standard or non F marked FSB. I'm wanting to find 3 nice carry handles for the extra rifles I am building and I'm concerned about whatever carry handles I buy being able to witness with whatever FSB I use. Can someone school me on the subject? if I decide to run FF rails up front, I will be less concerned but as it is now, I'd like to know. Thanks Dan |
|
I cant school you on the differences of the FSB, other than telling you that one is higher for the shorter sight distance of a carbine. I can help you find nice carry handles cheap |
The taller front sight bases are needed for use with flat-top upper receivers. Because of the distance between the sights you are less likely to -need- the taller front sight base with a rifle length system but it can still be an issue. My rifle length uppers have been about 50/50 when it comes to getting by with a flat-top upper and a standard FSB. |
|
f marked FSBs are a little taller than the standard FSB. You can always go with a bushmaster tall front sight post if needed. I think a lot depends on how you setup your rear sight. If you use a standard carry handle with the A2 style rear sights, you can add negative clicks for different distances that are shorter than the standard 300 meters and up settings. By adding negative clicks, the front sight needs to be raised to compensate. I have read that some people have done this on a standard FSB and did not need the taller post from Bushmaster. Others have needed it. I purchased the above carry handle and set it up with -7 clicks so that I can sight it in at 100 yards (-6 clicks on a 6/3 A2 carry handle). Apparently this does not affect the 6/3 zero at all. I downloaded the USMC manual for the M16A2 which also has the M4 in it, and they indicate that there should be 3 or 4 clicks below the 8/3 on the M16 (double the clicks for the 6/3 carry handle). They do not explain why, but it may be similar reasoning as the other methods of zeroing the A2 style sights, so that is the way I'm doing it. At 6/3, the rear sight only comes up about 1/16" or 1/32", so it may need a taller post. You can always go with the -1 click calibration and the rear sight will basically bottom out at 6/3; my carry handle came that way. There is a bunch of info on the A2 sight that I combed through to decide on how to sight it in. hopefully this makes some sense. If not, just try the carry handle and see how high the sight needs to be when you zero it. That will be the only way to tell if you will need a taller post or an F marked FSB. I think the "F" marking is for flattop, probably due to the carry handle and the carbine gas system being shorter than a standard A2 rifle length gas system. THIS thread gave me a lot of info on zeroing the carry handle. |
AR Sponsor