Quote:
Originally Posted by mrerick
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Respectfully suggest a great deal of caution with this kind of comparison.
Caveat 1:
There is really no such thing as “sub-machinegun ammunition”, as such. Sub-machineguns are just fully automatic firearms that fire a pistol cartridge. Countries that field sub-machineguns and pistols don’t have different types of cartridges for each.
Caveat 2:
There is no such thing as a single NATO standard 9x19 load. Different NATO signatories load their ammunition (pistol or rifle) to whatever standards they feel best meets their military goals.
Caveat 3:
CIP and SAMMI chamber pressures are measured using different methodologies and procedures and cannot be meaningfully compared.
Caveat 4:
Military ammunition is not subject to commercial laws, is usually made to perform to military standards, and may or may not be pressure tested using commercial policies, procedures or methods. This means that any extant published pressure data for military ammunition is irreconcilable with published pressures for commercial ammunition.
Caveat 5:
While chamber pressures and muzzle velocities are related, that relationship is neither direct nor linear. Higher chamber pressures don’t always result in higher muzzle velocities. Lower chamber pressures don’t always result in lower muzzle velocities.