Clearing up misconceptions about the 9x39 cartridge

Almost every time I read people talking about the 9x39 cartridge people always call it over-performing, calling it a fat, slow, bullet that shouldn't even penetrate kevlar vests, some even claim it shouldn't even be able to penetrate a flak vest.

Yes it is subsonic and yes it is a large and heavy round, however it was specifically designed to be both subsonic and penetrate armor very well.

The 9x39 sp6 cartridge is capable is able to pierce 8 mm steel at 100 m, 6 mm steel or 2.8mm titatium or 30 layers of kevlar at 200 m, 2 mm steel at 500 source

The “BP” bullet provides breaking through of a steel sheet with a thickness of 7 mm made of steel of grade St.3 at a distance of 100 m. source

For comparison, 5.56 caliber m995 ammo penetrates 12mm of steel at 100m source which is silly because in reality it is actually WEAKER than m855a1 ammunition which can penetrate 10mm of steel at almost 400 meters distance source

All in all the cartridges are actually designed from the ground up to defeat body armor. Here are some cutaways of the cartridges in question. https://imgur.com/a/NLaptL2

Also the gun is way louder in game than in real life... you can barely tell when you're being shot at by the thing at non-cqc distances, but that's another issue. source