Choate Tool 7&8 Shot Magazine Extension Spring 12 Gauge. magazine extensions. Specifications for Choate Tool 7&8 Shot Magazine Extension Spring for 12 Ga: Manufacturer: Choate Tool Country of Origin: USA Magazine Capacity: 7 Round Features of Choate Tool 7&8 Shot Magazine Extension Spring for 12 Ga 7 & 8 Shot Magazine Extension Springs For 12 Ga Package Contents: Choate Tool 7&8 Shot Magazine Extension Spring for 12 Ga Choate Tool CMT-60-09-11: 7&8 Shot Magazine Extension Spring 12 Gauge