AP Customs 3×3 Shotgun Shell Holder609824143445 The AP Customs 3x3 Shotshell Shell Carrier has been CNC machined from a solid aircraft aluminum billet, Hard Coat anodized to mil spec standards, and features 303 Hi Yield stainless retention springs. This double stack shotshell carrier is capable of holding six rounds of 12 gauge 2 " shotshells. The AP Customs 3x3 Shotshell Shell Carrier comes standard with a BladeTec Tec Lock.