Heckler & Koch MP7A1 (4,6 mm x 30)
Heckler & Koch MP5SD (9x19mm.)
Heckler & Koch MP5 (9x19mm.)
Haenel MP40 (9x19mm.)
The MP40 was used extensively by the German snipers as an additional weapon during World War II on the Eastern Front.
Snipers were often terribly afraid of being captured and because the sniper rifle often does not work well at long distances, many German snipers carried an MP40 as a backup weapon. As described in Albrecht Wacker's wonderful book.
There are also several cases known that people actually behaved and dressed in camoflage as a sniper armed with an MP40