I brought my gen 4 about 3 weeks ago. I have put about about 200 rounds down it. Works perfectly an very accurate.  Mostly shooting hand loads. 7.5g of wsf starline brass cci 300 180 speer tmj fn. Will work up some make loads with 800x an report back.

Excellent. Please keep us posted on how it handles the hot stuff. I have a buddy who just picked up a Gen 4, and he is looking for feed back / advice.

I loaded up some aa #9 15g with starline brass cci 300 primers 180g speer tmjs. All fired fine. No pressure signs

What kind of velocity are you getting with this load?

^^^
I have no idea no stand for my chrono was hoping someone here could tell me.

1300+fps is possible

Today shot 150 gain nosler jhp loaded with 10g of 800x. Fired great. Put thirty of them down range. What max for this load. I was thinking 10.5 from reading the underwood pull downs