We've all seen the videos, and what they don't tell you is most most ar's both do and piston are up to the same level, just make sure your barrel has no water in it. We can help but let's talk. First a price range, we won't judge, but without that it's too broad a selection. Btw, Colt is not cheap. Next comes range of use, how far do you want. Also keep in mind that it'll likely be over ten or eleven pounds. More depending on optics