Does anyone know if this set up for a 22 would be considered a silencer? if I know the laws right dont you have to register silencers? I would not want to go through all that B.S. I would just find another plinking 22 lr The H&K MP5 SD offered by Umarex USA is a rimfire rifle authentic in looks, feel, and operation. This HK clone is engineered as a dedicated .22 Long Rifle. Its built with a match grade precision barrel, metal receiver, and retractable stock. It also has a NAVY pistol grip as well as HK MP5-style sights. The sound dampener (SD) is actually a compensator. It is attached to conceal the 16.1 inch barrel that extends the full length of the gun and compensator. The MP5s magazine is made of high-strength polymer and is designed for ease of loading with dual grips for holding the spring when loading. A 25- and 10-round version of the magazine is available. Both are proportionate in size to the centerfire versions mag to maintain the authentic look of the 9mm MP5s magazine.