Civil War Era Colt Patent Brass. 31 Caliber Pocket Bullet Mold. This is a Civil War Era Colt Patent. 31 Caliber Brass Bullet Mold. The mold is stamped Colts Patent on the front and measures 4-3/4 Long x 5/8 Wide.The mold is in overall nice untouched condition. The cavities are in good condition and the mold closes tight and works smoothly. The item "Civil War Era Colt Patent Brass. 31 Caliber Pocket Bullet Mold" is in sale since Thursday, December 5, 2019. This item is in the category "Collectibles\Militaria\Civil War (1861-65)\Original Period Items\Other Civil War Original Items". The seller is "captainxo" and is located in Malverne, New York. This item can be shipped worldwide.