9mm AP capabilities vs. M17 / M18 ammunition

[simonrichter]

Hi Folks,

Maybe some of you has an answer to this issue that has long been puzzling me: The Russians managed to not only create the 9x21 AP round, but also to put more or less the same AP capability in a 9x19 as well (the 7N31).
In the light of these developments, I always wondered about the NATO PDW trials stacking standard 9mm against 5.7 and 4.6. While I see the benefits of the latter two in terms of recoil, weight and mag capacity, it's absurd to claim that they are better in piercing armor when no AP variant of 9mm was ever tested in these trials.
Even more, after most NATO countries opted to stick with 9mm at least as a pistol round anyway, why didn't they try a variant better against helmets and ballistic vests when this was obviously an issue in the PDW segment? Afaik, the new M17 / M18 doesn't make use of any kind of ammunition that has enhanced capabilities against soft body armor...?

 

[Rob228]

My guess is that it has to due with pistols not being primary weapons, the armor piercing capability comes from carbines and long guns.

Sheer guesswork on this second part: in today's political climate I don't think the major ammunition manufacturers want anything to do with handgun ammunition designed to penetrate body armor.

 

[TunnelRat]

Here's some interesting background about those NATO pdw trials. Around the 9:00 mark the narrator talks about the 7N31. It's worth noting that neither the HK 4.6x30mm nor the FN 5.7x28mm were capable of defeating the Russian body armor of the time, as per independent testing after the fact:
https://www.youtube.com/watch?v=Py9MJUmdQ4o

I think in current times given the prevalence and affordability of plates rated for rifle threats (even on the US commercial market), threats that could potentially be defeated by a more powerful 9mm (use of which would liken shorten the life of service pistols) are relatively far down the list of concerns. The US military is concerned that near peer threats will be fielding body armor that will defeat 5.56x45mm, much less pistol rounds.
https://www.youtube.com/watch?v=Lm0XId4kftg

Lastly, you can buy 9mm on the US commercial market that can defeat level IIIa body armor. Defeating higher level threats isn't as easy.
https://www.youtube.com/watch?v=Nr6h44Pu4sM