Bad RJ45's or bad crimper?

I've got an RJ45 crimper (forget the brand, it's not marked) that seems to work with some brands of RJ45's but not others. Trying to figure out if it's a cheap/worn crimper, or cheap RJ45's?..

On the failed crimps, it doesn't always crimp the outside pins (1,2 & 7,8) all the way. It looks like the teeth of the crimp head don't always hit square on the RJ45 pins and "slip" while crimping, actually noticeably bending the RJ45 pins a little.

What do you think, sign of bad /worn crimp head or cheap RJ45's?

Thanks in advance!