Kat,I have actually shot the 75gr. Ultimate Steel you speak of.I will say they fly very well,just like a field point.I won a package a couple of years ago at a 3-D shoot,but didn't hunt with them being they were too light for my setup.I'm already pushing it with a 100gr. tip and didn't want to chance it.If they would have been 100gr. heads I would of tried them for hunting.My buddy took a big 170 class buck with the 100's,which he spined and got good penetration.He did lose one blade,but I guess you can expect this with a spine shot.Those are some tough little broadheads to assemble,being their so tiny.You almost have to use tweezers to install the small blades,but the overall cutting diameter of the 75gr. is one inch.The blades are .036 thick bacon skinner blades,very sharp.I didn't experience any problems with the one I shot with it seating all the way in to the insert,like Rudd stated,I believe they corrected that problem.And the 75gr. have an one inch cutting diameter compared to the 100's 7/8".I just can't comment on the durability and blade retention of this head,being I have no experience hunting with them.Though they do seem like one little tough head.If you can remember the adds a couple of years ago,Ultimate Steel supposedly beat the Muzzy in the Brick Test for durability?Good luck with whatever head you select.