I know this is a newbie question but....

I recently bought a 20" Bushmaster standard A2 xm15-e2s target rifle.  

I now wish I would have bought the one with the removeable carry handle!

I just found out about ACOG's and they sound awesome!  I especially like the TA31F.  I have a feeling they are only meant for flattop though.  Am I right?  Do I have any options to mount an acog on my carry handle?

Pleasant surprises abound.. the ACOG is DESIGNED to be used with a carry handle; to mount to a flattop you actually need an adaptor.

I'm sorry but TA31F Chevron BDC was designed for use with 14.5" M4A1 flattop firing M855.

TA01, TA31 or TA31A will suit your needs though.

IMHO, On carrying handle, Compact ACOG is hands down better.

Damn!!

Oh well.....

I really do want an acog because I like the bullet drop compensator.......Which acogs are actually meant to be mounted on a 20" A2 rifle?  Are there any standard acogs?  I like the TA01, the TA11 and the TA31.  But if these are not meant for it, i guess i will have to go compact....

Thanks for you help!

There are two to three or MORE different verisons of every single ACOG. For example, the TA31 is available in three different configurations, the TA31, TA31A and TA31F.  Some are actually specifically designed to be mounted on a carry handle. Lucky for you, the three optics you mentioned were all meant to be mounted on rifles just like yours. If you want to get one made for your rifle, just be sure to get either the TAO1 or TAO1C (not the TAO1B or TAO1nsn), the TA31 or TA31A (not the TA31F) or the TA11, TA11B or TA11D (not the TA11C, TA11E, TA11F ot the TA11F-A). I know it can be confusing. But hang in there. To be honest with you, the scopes you want to avoid are generally less commonly available than the ones you need anyway.

Thank you new-arguy, you were very helpful!

I am now torn between the decision to get the TA01, TA31, or to get a compact ACOG (I like the TA50R-4)  My gun is mainly used for plinking, not really CQB.

What I don't understand about compact acogs is why people would choose other ones besides the TA50 series or 39 series with the higher magnification, and go for lower magnification?

Also, can you still use your iron sights with the full size acogs?

There's all sorts of reasons to go with lower power ACOGs. Quite possibly cheif among these reasons is to get more eye relief. Lower powered Comp ACOGs have very, very generous eye relief.

You will still be able to use your irons when mounting ABY magnified ACOG to the carry handle. The are all equipped with a sight channel in the base.