Supposed to be a bit over 10mm. Here's what the hottest round I have is supposed to do. I have a 5" ported barrel.

Caliber : 40 Super

Bullet : 135gr. Nosler Jacketed Hollow Point.

Ballistics : 1755fps / 923 ft.lbs. - Glock 21 6" barrel
1685fps / 841 ft lbs 1911 5" barrel