I shot some of the 180 gr, 1100 fps .45 ACP KTW'S.
back in 1978. They grouped 5" at 50 yds, from my Lee Machine Rest, and didn't do much more than a hot, hard cast swc did against steel, wood, or concrete. They did, however, pierce a 24 Layer Safariland vest, and go thru an additional 2+" deep into hard frozen dirt. When I recovered some of the bullets from a snow bank, the teflon was GONE, rubbed-burned off in the barrel.
IIRC several companies used to offer a loading "Teflon/Nylon" coated specifically for indoor ranges to reduce airborne lead dust. These loads were also banned IIRC. I do not approve of any "Cop Killer" bullets, but to be such they must be shot at cops IMNSHO.
There was a brand of ammo a while back called Nyclad that I think were nylon or Teflon coated. But the lead was very soft and the coating was to keep the barrels from leading up excessively. Had nothing at all to do with armor piercing at all. But I guess that got swept into the illegal bin as well.