SNS Hi-Tek coated lead and barrel leading?

[fredj338]

I suspect your loading technique. I shoot hi-trek coated, no leading, but only running max of 1000fps. Over crimping, not enough flare at the case mouth, the coating will be broken. I've just started doing my own coated, so I will exp more with higher vel, but it should be good to 1600fps +.
Fwiw, WSF is a great 9mm powder. It is a medium burner, not fast at all. I find it a bit slower than Unique. Your 5.3gr load is running hard, but not max in most guns, at least my exp.