Wis,

I'm sure that's not the kind of scope he was referring to. In fact, a Red Dot is not a scope at all.

Infantry,
There are quite a few scopes that can be used for 3D. Most of the better ones use Feathervision lenses. I have limited experience the last few years on which brands are the very best, but I've used the Bullseye Millenium Grande and CR Apex. Both are very good quality and come in several different diopter lenses.

I might suggest that you jump on over to www.archerytalk.com. You should be able to get a bunch of info there as there are a lot of target and 3D shooters on it.