KEL P50 RIFLE KIT 5.7X28 FOLDING STOCK When we launched the P50 several years ago, we were immediately asked about an option to convert a P50 into a rifle. We are thrilled to announce the P50-1200KT Rifle Kit. This will allow a customer to convert their current P50 into a rifle after following the proper rules and regulations with the ATF. You simply unscrew one pen and drop the new lower into place. DESCRIPTION: P50 RIFLE KIT CALIBER: 5.7x28mm