Caleb wrote an interesting blog post last month about the the different in pressure between the SAAMI spec’ed 9mm loads (9mm Luger / Parabellum) and the NATO load (9x19mm NATO). I had forgotten to mention it here until I was browsing his blog today.
The ammo industry uses something called SAAMI Standards to establish the pressures that ammo should be loaded to. The SAAMI pressure for 9mm Luger ammo is around 35,000 PSI, and C.I.P (think European SAAMI) rates 9mm Luger ammo at 34,080 PSI. According to documentation, the 9mm NATO rounds are pressured at 36,500 PSI (again according to CIP). That means that when compared to standard 9mm ammo, the 9mm NATO ammo is running a higher pressure, analogous to a 9mm +P load, which SAAMI rates around 36,000 PSI.
Read the full post here.