40 gr bullet are pushing the limit at 200 in my eyes. I shoot 50gr V-Max in my 223 and 300 yards shots are easy. Never met a 22-250 that wasn't picky. Great round but every one I have ever seen the owner says it took a lot of work to get it shooting great.
It may be the rifle. Had a buddy that took 2 years of tweekin to find a good load for his 22-250 sps.
Try different powder. Varget is a powder i don't hear much about in the 22-250.
Sierra list 36 gr of RL-15 for the accuracy load with 50gr bullet CAUTION THIS IS A MAX LOAD BACK OFF TO 34.5GR AND WORK UP.