SAAMI – Rifle

SAAMI maximum chamber pressure for specific cartridges.

CartridgeCUPS PSI
22 LR24,000
6.5 Creedmoor62,000
6.5 Grendel52,000
7.62 x 39mm45,000
223 Rem52,00055,000
243 Win52c0060,000
270 Win52,00065,000
30-06 Win50,00042,000
30-30 Win38,00042,000
300 ACC Blackout55,000
375 H&H62,000
300 Win Mag54,00064,000
303 British45,00049,000
308 Win52,00062,000
44-40 Win13,00011,000
45-70 Gov’t
See Special


SAAMI ( Sporting Arms and Ammunition Manufacturing Institute) is an organization that defines extensive definitions for cartridges of ammunition. It includes the cartridge physical dimensions as well as maximum chamber pressure. This ensures that ammunition manufactured as a specific caliber is safe for that type of firearms with assuming a firearm in a good functioning condition.

Copper Unit of Pressure (CUP) is a measurement used in the ammunition industry to determine the chamber pressure created by a cartridge load. Originally, a precisely formed copper slug was placed in a fixture over the chamber. When the cartridge was fired, the amount of crushing measured on the slug allowed engineers to determine the pressure.

These days, modern electronic transducers provide faster, more accurate measurements of chamber pressures in pounds per square inch (PSI). CUP and PSI are measured to different scales and are NOT interchangeable.