Complete nonsense. Many years ago some manufacturers experimented with steel bullets to increase penetration. The hard steel would wear out barrels much faster than softer copper or lead, so the bullets were coated with Teflon to prevent barrel damage. The MSM called these "cop-killer bullets"; the denser material may have been better at penetrating body armor but the Teflon didn't have a thing to do with it.
The Viet Nam “flack vests” were to stop shrapnel and not bullets. The one that I wore was filled with a fiberglass mat. I really don't care if you call me a liar or not but you should at least use facts.
I also thing if you bother to look up Teflon you would find several theories.