I have not shot the 165gr. "X"'s but, I have shot 150-168gr. "X"'s, in my .300WM.
Try 78.5gr. RL22 with that bullet.
Also got good results with:
IMR4831 and H4350 with the 150-168gr.
The RL22 will give you the best velosity though.
That RL22 load with a 168gr. XLC went 3125 fps. About 100fps faster than the other 2 I mentioned. Email me if you need some more loads for hunting. I got a bunch!!..sakofan..