Sounds like a public affair affair based on nothing but hot air !
Maybe they haven't heard of the simple CZ52 with a 223 Timbs or .224 Boz load. Been around a decade er two in one form or another.
I have an FN 5.7 Pistol on order from my local gunrunner....will advise as to it's scary ability after a few hunnerd rounds downrange.
Stay safe !
That 7.62x25 is a vest shredder, and the Timbs at 1800 fps are speedy little puppies