The subtle radius of each shell holder mouth ensures smooth and reliable functioning. The retainer spring is designed to stay in place when inserting cases into the shell plate.A single shell plate may be used for multiple calibers. Common Calibers are listed for each. Please call for complete list.Shell Plate Sizes:#1 - (22-250 Rem, 308 Winchester, 30-06 Springfield)#5 - (7mm Remington Magnum, 300 Winchester Magnum, 338 Winchester Magnum)#6 - (38 Special, 357 Magnum, 7.62x39mm)#8 - (30 Luger, 38 Super, 9mm Luger)#10 - (357 Sig, 40 S&W, 10mm Auto)#16 - (17 Remington, 204 Ruger, 223 Remington)#45 - (45 ACP, 45 Winchester Magnum)