We're essentially in agreement, all I've been saying is your original statement that 5.7 would be effective for countering modern armor nations like China that you linked pics to wasn't correct. 5.7 is easily the best penetration performing pistol round of standard manufacture and availability, however it still is no match for the cheapest ceramic plate systems, including what the Chinese are and will be using. Yes the 193 round penetrated that 3a shoulder piece. The SS190 AP will usually get through 3a. Again, against the best soft 3a armor you can get, the ball 5.7 doesn't always penetrate, hence DIJ giving it a marginal rating for penetration vs 3a. The reality is if the military used it, it WOULD be using the illegal for civilians in the USA to own SS190, which would be most times effective vs soft 3a. This isn't the point, or the one which you initially brought up, that choosing 5.7 because it would be effective vs modern infantry ceramic armor systems. It isn't.
Most nations are equipping their troops with lvl 4, again, which 5.7 will NOT get through. Multiple shots in the same place? That's your plan? How likely or possible do you think that is? How many rounds would it take in precisely the same spot to defeat a cheap ceramic plate with 5.7 - I'm wagering double digits, since 762x54 steel core Russian AP will be stopped even with multiple hits on a decent plate. Again, in that vid I posted, of which there are many, 762 Nato WILL stop several rounds in the plate from point blank range with the cheapest 140$ plates you can get. High end systems like Paracleet, Scale, etc, can and have stopped multiple hits from various 30 cal rifle rounds, AR500 plates will stop rounds in the same place, there are tests and videos of it taking over 10 hits and not failing. How many rounds do you think 5.7 will need? It's ridiculous trying to defend your original supposition by now saying all that's needed is a ton of multiple hits in the precise same spot, and now you're correct, 5.7 will beat a plate armor system. Is 5.7 the best penetrating standard handgun round out there - yes, probably. Is it one of the better options - again, probably. Will it defeat the armor which nearly all potential enemies will be wearing in the next 1/2 decade - no.
Believe me, I know how capable it is, I've seen it when it was first coming around being demo'd by the factory reps. At BW in 2004 they had a new cockpit door that the manufacturer rated against all kinds of pistol ammunition, and they were very surprised when 5.7 defeated it in front of hundreds of people. It still will not make any difference versus lvl 4 ceramic plate - none. It is very effective for what it is designed for, beating threats wearing soft armor or getting through other light barriers. In Canada we don't have a law forbidding the use of SS190 ammo, and I've shot thousands of rounds of it through both the 5.7 FN pistol and the P90 semi auto carbine with a longer barrel than the typical subgun. I have an AR upper that uses it as well. It has very controllable recoil, limited flash, excellent accuracy, and amazing penetration. The controls are awful on the pistol, and IMO a steel framed pistol is what the military needs for longevity and service life - a simple DA/SA 20 round steel framed pistol with standard controls and decocker would be perfect for a "new" military pistol in 5.7 IMO.
http://www.guns.com/review/2013/12/03/ar500-armor-part-ii-will-defeat-video/The above plates are cheap, and only lvl 3, and look what it takes to defeat it - 50 cal 750 gr Amax barely broke through, and this is 10 year old tech. In another decade, our potential threats will have this and more.
