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Unread 02-14-2019, 04:09 PM   #29
Kyrie
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Quote:
Originally Posted by Patrick Sweeney View Post
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And Kyrie, where did those pages come form
Technical Manual number is at top, right, corner of each page.

Quote:
Originally Posted by Patrick Sweeney View Post
Did the Army really print technical data on 9mm cartridges that lists the bullet weights as 182 and 179 grains?
No sir, they did not. But they did list the cartridge weights as 182 and 179 grains :-)

Quote:
Originally Posted by Patrick Sweeney View Post
Finally, the MAP, Maximum Average Pressure, is a ceiling, not a goal.
Correct. ANSI/SAAMI Z299,3 – 2015 “Maximum Average Pressure - is the recommended maximum pressure level for loading commercial sporting ammunition.”

Quote:
Originally Posted by Patrick Sweeney View Post
If an ammo maker can get the velocity they want, at a lower pressure, they will. So, if the goal is (for example) a 115 grain bullet, at 1,200 fps, and they can do it with the powder you have, at 27,000 PSI, then they'll do it.
Correct. Some people confuse the SAAMI MAP with a “service pressure”. That is not the case, and “service pressure” doesn’t even exist as a concept in SAAMI. Moreover, some people tend to equate higher peak chamber pressure with higher muzzle velocity. That may or may not be true in any specific case. Muzzle velocity and peak chamber pressure are only vaguely related, and in some cases may actually be inversely related. Peak chamber pressure is not a good predictor of muzzle velocity.

SAAMI has performance as the goal, with that stated performance to be attained without exceeding some stated average peak chamber pressure (“Maximum Probable Sample Mean"; MPSM).
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