Howa mini stock accuracy issues

[Dt219]

I just picked up a new howa mini 20” in 6.5. I took the stock off to sand on as it was touching on one side. Anyways I got it opened up and went out to break it in and get a general idea as to how accurate a grendel bolt gun could be. Well results was a little disappointing. Some factory ammo would shoot 1” one minute and 2” the next. My reloads acted about the same which was weird to me as well as my poi changed also numerous times. The stock alone is not a prize in my opinion but not pure trash either, the bottom plastic however is pure trash. Yea I know it was a $500 gun and it shoots but could the bottom plastic cause the stock to warp or twist from uneven torque one way or the other. I know it has pillars installed but they are about pointless using the factory bottom metal. I don’t think it’s a stable enough platform from the factory