Why Your MP5 Upper Receiver Matters So Much
If you're building a clone or just trying to fix up an old roller-lock, finding the right mp5 upper receiver is basically the most important step in the whole process. It's the heart of the gun, the part that actually makes the magic happen, and—legally speaking—the part that actually is the gun. Unlike an AR-15 where the lower is the serialized part, with the MP5, everything revolves around that stamped steel upper. If you get a bad one, you're looking at a world of headaches, from cycling issues to optics that just won't zero. ...