I am in the process of getting an optic for my 16" weapon. It has a LMT upper with DD rails. The upper has a fixed front sight. The problem is this: I would like to get an EOtech 510 or 510AA, but I would also like to get an ACOG, probably the TA01NSN or TA01. I will be building a 20" weapon soon as well and thought about waiting on the ACOG and putting the ACOG on that weapon. Now, I would like to have a higher amount of magnification on the 20" weapon and I want to go with a Leopold or a Schmidt and Bender. So, should I get the ACOG on the 16" and forget about the EOtech or should I get the EOtech 510 or 510AA on the 16" and put the ACOG on the 20"? Also, kind of a seperate question, but does anyone know how the ACOG TA01NSN would handle bullet drop if I did not use 62 grain ammo? The BDC marks on the TA01NSN are designed around the 62 grain round the Marine Corps and SpecOps are using now, so if I dont use that grain ammo, you think the sight would handle significantly different, or should I put on the TA01?