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12/6/2019 7:27:02 PM
Posted: 6/3/2008 3:20:25 AM EST
I am about ready to order my upper from Del-ton. But I have a question. The trend seems to be a flat top upper. My question is, how does a full size front sight affect the use of an optic sitting right on top of the upper. Does the FSB get in the way? It looks like it would. A related question is, If I get an A-2 upper, is the optic mounted on top of the carry handle sitting so high that is is awkward?

Super Noob questions but still......Inquiring minds want to know.
Link Posted: 6/3/2008 3:50:51 AM EST
the FSB can be a bother for some people, others don't seem to mind it.

i didn't like it, so i went with a free floated rail and a folding front and rear sight.

if you're using a red dot type sight, i find that the fixed FSB makes the sight picture a bit too "busy" for lack of a better word.

something like an ACOG however, if it's over 3-4x the FSB will just be a barely noticeable shadow in the lower portion of the window.

as far as optics on an A2 type upper, they're a bit high but not unreasonably so, i would certainly suggest trying before you buy, though.

Link Posted: 6/3/2008 11:00:21 AM EST
With a 2-7x32 Nikon on my otherwise stock M4gery I couldn't see the FSB even on 2 power. I don't understand how it works, but it does.
Link Posted: 6/3/2008 4:16:19 PM EST
I'm not sure if you're referring to a red-dot style optic or not but I use an EOTech 512 with fixed front sight base on flat-top M4gery. I am using a perfect Co-witness without problem...the front sight sort of disappears for me when I concentrate on the target or the EOTech. As another option, I've used a friends carbine with fixed FSB and an Aimpoint with riser using a 1/3 co-witness which puts the front sight lower in your optic.
Link Posted: 6/3/2008 6:19:53 PM EST
At anything over 4x you won't see the FSB at all, at 2-3x you may get a shadow, this is somewhat subjective as well as relative to the optic in question and may some something to do w/objective dia/etc.
As mentioned, optics work ok mounted on the carry handle, but you'll likely prefer the flat-top version. Much more practical.
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