OK , I have a Nikon scope mounted on a LaRue SPR -1.5 on my flat top AR. Now, mounted like that , at that height (1.5") the Nikon scope hits the front sight square in the middle. I know that I notice it very little , but… What happens if I add a 1/2" rail so that the scope will raise that amount and then clear the sight completely ? my question is to the effect of zeroing and in general … I know that the scope is suppose to be at an ideal 1.5 inch . Would I be able to calibrate the scope and use the mildot cards as if it were at 1.5" height? Will it make any difference ? I will like someone to reply with detail to this …!!! Thanks to all … josey88
Most disagree but I use a LaRue 1.93" mount to run a 1.5-5 Leupold scope. It clears the FSB and works for me. On my 3.5-10 I use the 1.5" mount but use a flip up front sight. I noticed a glare sometimes from the FSB, even though I could not see the FSB.
I noticed the 1.93 mount when used with 1" rings is not quite that tall. In fact it is closer to the Aimpoint mount than the 1.5 scope mount, height wise.
My advise would be to get rid of that FSB completely, especially since you’re using a high powered scope. If you really think you may someday need the FSB, I’d still remove the FSB and save up for a railed handguard and some flip up BUIS.
There’s many ways to remove the FSB for optics, the cheapest way is to shave it off with a dremel tool, then repaint it (I’ll find you some detailed instructions on how to do this if you’re interested), or you could spend $40 and get a gas block (which replaces the FSB altogether), which you could also mount a flip-up front sight to that as well.
As far as raising the scope - no, the mil-dots will range the same no matter how high up the scope is. If you’re using the dots for BDC, then you’ll need to re-calculate you’re range data with the new height entered.
http://www.eskimo.com/~jbm/cgi-bin/jbmcard-5.0.cgi