Now that’s a fun topic right there – as in, what’s the difference between ammo that’s loaded to 9mm NATO pressures and ammo that’s loaded to 9mm Luger pressures? First off, you have to establish that there is a difference, because there are people out there who will fight and argue that NATO spec ammo is exactly the same as commercial 9mm Luger. It’s not, trust me. Aside from the obvious difference in bullet weight (9mm NATO is 124 grain, most commercial plinking 9mm ammo is 115 grain) rounds that are loaded to NATO spec are loaded to a higher pressure than rounds loaded to industry standard.
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.
So what does this mean for you? Well, a lot of people recommend treating 9mm NATO rounds the same way you’d treat a 9mm Luger +P, which is to say understand that it’s loaded to a higher pressure than your garden variety 9mm Luger ammo. For the casual shooter, this means a couple of things: don’t put 9mm NATO ammo in older guns. Only use it in modern, robust guns in good condition. Remember that 9mm NATO is the standard service cartridge for something like half the planet, which means that it’s in use in wide variety of pistols, including the following:
- Beretta M9
- Browning Hi-Power
- Glock 17 and 19
- All manner of Sigs
The short answer is that an occasional diet of 9mm NATO isn’t going to hurt your gun, provided it’s a well made modern gun. I certainly would not put 9mm NATO ammo into a Hi-Point, because I don’t want to eat the slide and I don’t trust a blowback operated gun with a zinc slide to stay together. But if you’re running a Springfield Armory 1911 in 9mm, or a well made pistol from a well made manufacturer you should be fine.
However, what you should be aware of is that a steady diet of 9mm NATO ammo, or 9mm +P ammo is going to increase the wear and tear on your heater. If you’re just going to the range every now and then, it’s not going to affect you very much. However, if you’re shooting 500-1000 rounds a month, you will end up seeing internal wear quicker than you would with standard pressure ammunition. But if you find a good deal on a bunch of 9mm NATO ammo, and you’re worried about running it in your Glock 17, you should be fine.*
*User assumes all risks when using overpressure or +P ammo, and accepts that using firearms is inherently dangerous