MAP (Maximum Average Pressure)
Definition
The SAAMI statistical upper bound for chamber pressure in a given cartridge specification, expressed in PSI. The CIP equivalent is published in MPa under the TDCC standard. Forensic over-pressure determinations compare reconstruction estimates against these figures.
- Full name
- Maximum Average Pressure
- Standards body
- SAAMI
- Unit
- PSI
- CIP equivalent
- Published in MPa under the TDCC standard
- Forensic use
- Benchmark for over-pressure reconstruction
Common questions
Why do SAAMI and CIP publish separate pressure figures for the same cartridge?+
SAAMI is the North American voluntary industry standards body and CIP is the European regulatory body, and they use different test methods and pressure-measurement conventions, so their published figures for a given cartridge are not always numerically identical even when they describe comparable safe limits.
How is MAP used in a firearm failure or over-pressure investigation?+
An examiner estimates the pressure that would have been generated at the time of the incident, from case-head expansion, propellant load, or pressure-trace testing, and compares that estimate against the published MAP to judge whether the round or load exceeded the specification the firearm was designed for.
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