I have a TA31F on my Bushmaster carbine that I tried setting on my FS2000 and it seems like it would work great. I do not want to rob my Ar so I am looking at another ACOG, TA31 DOC that seems like it would work great with the DOC fast sight. The only thing is that I prefer the red Chevron to the Crosshair of the TA31 DOC. Has anyone tried a TA31 DOC on an FS2000?