I assume it falls into the category of phony-baloney:
The guy says that it is “Tungsten core AP” “Maybe prototype” “will blast through a manhole cover”. So at first I assumed it was just some M61 steel-core bullets that had been tumbled in moly, but then when you look at the photos you see that they are hollow-points. I’m thinking; how can a HP bullet penetrate a manhole cover? I figured these are either clad steel HP bullets which have been coated in moly, and are thus attracted to a magnet, or else they are possibly Winchester Fail-Safe’s which had a moly coating and which had the tungsten cup thingy in the core of the bullet which might cause magnetism?