>>64025840You'll need a special lower that's compatible, SSs are an AR trigger so you're looking for an AR trigger compatible MP5 lower. You'll need the SS itself, sometimes they are drop in but some times you may need to do some fitting. You will also need a "trip" for it. Pretty much the bolt on the MP5 isn't the right size/shape to work with the SS so you need a part to fix that. Last I heard you actually want one of the plastic trips and not a metal one, they're a sacrificial part and the weight of the metal ones tend to cause problems. I'd wait for someone who's done it to chime in too, that's just based on my own off and on research on SSing the MP5