If I remeber correctly all the new barells are drilled and tapped to accept a scope base. I have seen the normal Weaver style base installed and an Ultra Dot or similar tube style red dot attched. If you intend on using a Docter or C-More STS, they can be aobtained with Weaver style mounts. You should also check out BME as they have a wide assortment of mounts for target semi auto's.