Magpul

Lightweight but incredibly strong, Magpul's PMAG D-50 MP is a highly reliable, 9x19mm Parabellum, 50-round drum magazine for HK94/MP5 large-format pistols and pistol caliber carbines.It's unique drum configuration keeps the height of the magazine manageable, allowing for prone firing and easier storage. For easy loading, it includes a ratcheting loading lever that removes tension from the internal spring. They've also included a rounds-remaining rear window, a high-visibility follower and a capacity indication roller.