Elevation may have something to do with your stability.
I'm at about 500' -- give or take a few. I've tried several Remington and Ruger rifles in 243. Things look good in the summer, then go to Hell in the winter. Most of my shooting at distance is after the crops come out and through the winter months.
I've yet to find a factory 9 or 9 1/4 twist that will stabilize 105's regularly where and when I shoot. I know they may exist and perform better in other areas, but I've yet to find Nirvana with the factory twist in 10-12 samples. They've all keyholed at some point.
