My intention here is to showcase the versatility of the G21. All of the following loads can be fired from(with proper modification) a G21. These loads are from Buffalo Bore(from a 5" semi auto pistol barrel)and do not represent all of the manufacturers that offer these loads: 10MM 155gr TAC XP 1455fps 728ft lbs 180gr JHP 1350fps 728ft lbs 200gr FMJ 1244fps 687ft lbs 220gr HCFN 1200fps 703ft lbs 45 SUPER 185gr JHP 1330fps 726ft lbs 200gr JHP 1235fps 677ft lbs 230gr FMJ 1133fps 656ft lbs 230gr JHP 1131fps 653ft lbs 255gr HCFN 1095fps 672ft lbs 460 Rowland 185gr JHP 1500fps 924ft lbs 230gr FMJ 1350fps 931ft lbs 230gr JHP 1350fps 931ft lbs 255gr HCFN 1300fps 957ft lbs These loads are from Double Tap exclusively(from a 5" semi auto pistol barrel). *40 Super uses a necked down case: 40 Super 135gr JHP 1685fps 841ft lbs 180gr JHP 1400fps 784ft lbs 200gr FMJ 1300fps 750ft lbs 200gr JHP 1300fps 750ft lbs These loads are from Underwood Ammo(assumes 5" test barrel) and do not represent all of the manufacturers that offer these loads. *400 Corbon uses a necked down case: 400 Corbon 135gr JHP 1500fps 675ft lbs 155gr JHP 1400fps 675ft lbs 165gr JHP 1300fps 619ft lbs 10MM, 40 Super and 400 Corbon bullets are .400" in diameter, 45 SUPER and .460 Rowland bullets are .451" in diameter. I did not include 45 ACP/+P because they do not share the velocity of the above loads.