Rebarrel it. After having first hand experience with Christensen rifles and read others problems with terrible grouping that should fix the problem. It's a chronic thing unfortunately. Probably why it was for sale.
Have you looked at Two Vets? https://twovetssportinggoods.com/
I've got their Q.D.T. that I use and it works great for gun mounted shooting. They have several models that would be great for pack hunting too. Prices are good too.
Here's another cheap method. Two pieces of 1/8" aluminum (what was on hand) jb welded together and bolted to a $12 arca clamp off Ebay or Amazon. Just bent it by hand in the vise for the proper fit. Rifle specific but hasn't failed.