The SS109 green tip will go through lots of body armor. I would be sorry to not be aware that they most certainly should have some stock 9mm penetrator type ammo since 9mm has so much overpenetration anyhow. And yes you can buy armor piercing rifle ammo that I am aware of. And no teflon does not make a 9mm ball go through body armor unless its teflon and steel core combined or steel core only. Teflon 9mm ball without a precision intergral shifting steel core would only help it go through a piece of glass a little smoother not likely any body armor. I think you can't "fashion" armor piercing pistol ammo like 9mm with only a Teflon type composition spray coating unless you could simulate charachteristic materials like the tip material of a hornady mach 2 on the tip of a 9mm bullet which sounds possible might look sorta like a glaser safety cartride though. Strange anyhow that would only work on soft type armor so the professional manufactured kind is definately better. Mabey a Barnes solid copper bullet with a nail impressioned deep in it will penetrate vests especially if its a high powered rifle cartridge or 9mm fmj bullet.