Oh, there are certainly handgun rounds that will punch through many types of IIIA, though IIIA is a frustratingly broad class of armor. I needed a refresher course in the exact statistics, so I did a little research over the last few days.
The biggest factor in Kevlar penetration is bullet shape and composition. Simple Copper solids out of a 5.7 pistol will punch straight through most forms of IIIA armor, several layers of it, actually.
You'll have to forgive the random timestamps, if they come up, just re-set to 0:00.
5.7x28mm, Elite Ammunition 28gr T6 (All copper), VS Level IIIA Body Armor, FiveSeveN
5.7x28mm, 36gr Copper Solid, DevastaTOR 2.0, Elite Ammunition Velocity, Gel, Armor
What Is the Black Dragon Fang 5.7x28mm from Vanguard Outfitters? Ballistic Test! Buffman - R.A.N.G.E. • 142K views
Fort Scott Ammo Test Pt 2
9x19mm, 65gr SCB, Xtreme Defender, Underwood (#863), Can it penetrate soft armor?
Ventura 10mm Lehigh Extreme Defense/Penetrator Armor Test
Can the "World's Fastest" Production Pistol Defeat Armor? FK Brno 7.5mm vs. IIIA Armor
22tcm vs 5.7x28 vs 7.62x25
PSM Shooting: 5.45x18mm vs 7.62x25mm on Soft Armor
Important to note the 22TCM penetrates despite being a lead-tipped hollow point, and that 7.62x25 penetrates some IIIA kevlar but not others. Frustratingly, "Xtreme Penetrators" are significantly inferior to "Xtreme Defense/Defender" rounds in defeating armor, due to the higher speed and smaller contact surface of the later.
The similarity of Brno 7.5 to 9x25 Dillon (and the 9x25s FMJ/Solid copper monoliths VS FK's hollowpoint-only) suggests to me that 9x25 Dillion would penetrate, if anything, better.
I suspect .357 sig with "Xtreme Defender" would punch though, but on inspection there doesnt seem to be any advantage, Fort Scott doesnt make any conical rounds for it like they do 9mm, anyway.
After doing some research, these appear to be the options for AP civilian handgun usage.
5.7
the FN 5.7 is too expensive, but the Ruger 57 might be viable, we'll have to see where the price settles once it comes out, and if it isn't, you know, a piece of shit.
Price:
??? (I think the preorders for the 57 are <600)
9mm
+P Xtreme Defender rounds can penetrate some IIIAs, though Fort Scott conicals seem more viable.
Price:
~$600 While a full length 9mm can be had cheaper, and may work, a longer barrel would probably be advised.
22TCM
Not many choices here, one bullet and basically one gun. That said, the lack of FMJ available after a cursory search (with some JHP listed as FMJ maddeningly enough) rustles my jimmies in a deep way even though it's still capable of penetrating IIIA with JHP. As I said before, IIIA is a wide range, and while TCM might be just as good as any other in it's field, the missed potential of an FMJ or copper solid in .22TCM is very frustrating.
Also, this round really benefits from a 6" barrel, but those are all custom jobs, more wasted potential.
Price:
$600-$700 for a full size RIA. These usually come with an easy conversion to 9mm included, so thats a bonus.
9x25 Dillon
You'd more or less have to just do a long-barreled glock conversion, but with similar velocity to the TCM and 7.5 BRNO, and marginally more energy behind the same projectile design that worked best for the 10mm, with a smaller diameter, I think this is definitely something that could work. You could theoretically reload Fort Scott's into these for a fantastically penetrative bullet, but I'm really not looking at reloading for this thought experiment.
Price:
$700-$800 was what I saw as estimates on buying the right glock and converting it.
Until I save up more money, anyway, I'll just be eternally seething that no one's thought to make Copper Solids for 7.62x25 Tokarev.