is there data as to 22 ammo pressures?

[midland man]

i been wondering just out of curosity, whats the pressures in psi for 22 shorts, longs, long rifles and 22 magnums? thanks for your help?

 

[DocRock]

SAAMI max pressure is 21,000 psi for short and 24,000 psi for Long, LR and Winchester Magnum.

http://www.lasc.us/SAAMIMaxPressure.htm

 

[lysanderxiii]

.22 Caliber Short:
Maximum Average Pressure = 21,000 psi
Maximum Probable Lot Mean Pressure = 21,500 psi
Maximum Probable Sample Mean Pressure = 22,300 psi

.22 Caliber Long and .22 Caliber Long Rifle:
Maximum Average Pressure = 24,000 psi
Maximum Probable Lot Mean Pressure = 24,600 psi
Maximum Probable Sample Mean Pressure = 25,500 psi

.22 Winchester Magnum:
Maximum Average Pressure = 24,000 psi
Maximum Probable Lot Mean Pressure = 25,500 psi
Maximum Probable Sample Mean Pressure = 27,800 psi

The Maximum Average Pressure (MAP) is an average, some will be below it, and some will be above it. How much above the average is acceptable?
The Maximum Probable Lot Mean Pressure (MPLM) is two standard deviations above the MAP, this defines two things, 1) the maximum allowable standard deviation, and 2) the maximum value that 97.5% of all ammunition will be below.
The Maximum Probable Sample Mean is three standard deviations above the MPLM, and is the maximum pressure that should ever be seen within a lot.

 

[illinoisburt]

Had never really thought of 22 rimfire pressure before. Always assumed it was low, however those numbers are higher than many of the older standard pistol cartridges like 38 special, 32 & 45 acp.

 

[748]

It doesn't seem possible that CCI 22LR "stingers" are under 24,000psi.

 

[Riomouse911]

Stingers do use lighter bullets and a longer case... and possibly slower powder blends (maybe?)..to fire the bullet. That’ll give a higher velocity with the same pressures.

As for powder differences; I often see in reloading guides different powders will reach a specified pressure, but have much different velocities, with the same bullet.

What surprises me is the WMR is the same pressure, I would’ve bet they were at least 30,000 psi. Those rounds must use slower powders, as the report and flash when fired in a handgun is centerfire-quality for sure .

Stay safe.