If you want a 50 round magazine for your Master Piece Arms 9mm pistol or rifle, then this is the product for you. They start out life as two new Sten magazines and are meticulously welded together to create a monster 50 round magazine. They are not the cheap imitations but high quality mags, matched to fit the MPA930 & 30 series guns. Each mag is inspected after welding, feed lips are machined evenly, deburred on the inside, feed angle is matched, the followers are checked for smooth movement, a new 20 inch spring is installed and oiled. Please call if you have any questions on which mag works with your gun. We recommend the NEW speed loader with this magazine. For the correct speed loader for this magazine, please go to our page on Magazine Speed Loaders. *Approximately 2-3 week delivery time, Call before ordering.