The glove rating/measurement is not based on the weight of the glove itself, or the thickness of the padding. It refers to the amount of insulation of blunt force the padding provides. If a denser foam is used then the pad will be thinner, if the foam is less dense then the pad will be thicker. The visible thickness of the glove means absolutely nothing in terms of the protection it affords.
That said, the UFC uses 4 oz gloves just like every other organization in MMA, no matter what you think you see.
Thanx alot for the clarification on that one!
But still.. the padding on UFC gloves seem to stretch over a much larger area. But okey, I'll buy your explanation for now!
A second thought thou.. "It refers to the amount of insulation of blunt force the padding provides", I'd really like to know how they define this and how they're measuriing it. Because I think it can differ a lot if you put less dense foam and then throwing short distance punches(like kidney punches from mount) though the construction of the gloves won't matter when exchanging haymakers.