22-250 1:9" twist LRPV

I bought one of these to use in factory class score matches (mainly at 100 & 200yds, with a couple of 300 and 400yd matches per year).
What powder / bullet have you guys had the best luck with in this gun? I've been trying to work up something with the 75gr Amax. I've tried RL-15, H414, H4350, H4895, IMR4831, and Varget. RL-15 has given the best results with the bullets just kissing the lands. The three 3 shot groups I shot at 100yds averaged around 0.300". Velocity was around 3250fps. I'm using Lapua brass and 210M primers. I haven't tried different primers yet.
Is there a better bullet to use with this twist? I think the Amax could be on the edge of being stable in this twist, but I'm anxious to hear what you guys have to say.
Also, all of my error is vertical with this combination. I've heard that fiddling with the action screws can help with this. Which screw should I mess with, and what torque range? My stock has been bedded. I shoot pretty much free recoil off a SEB coaxial rest, and do not grip the forend at all. Thanks.

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69 gr SMK and Reloader 15 works for me I want to try some 414 sometime....

i'm shooting a model 12 26" factory barrel oal 2.345" 36 grains varget 50 grain v max .25" @100yards not sure of the twist rate bought the gun used