8208XBR should be the powder you try next.
Some people swear by 335, i swear at it. Nothing i've loaded in 308 or 223/5.56 shot worth a damn with it. The XBR burns a tad slower than the 335 just under the AA2230 / Xterminator burn rate. BUT it's a/12 stick not full like Varget or Benchmark. Or the ball like what your using.
This is 6 rds @ 100 yds off a bipod. I don't know what the velocity is, i go for accuracy. This load did what i wanted so i run with it.
You might try a 175 sierras before dumping the 175 bullet.