I've shot my 6.5 RPR a couple of times ( mainly at 100 yds but also at 300 once on Century) and rather like it.
Ammo wise, I've tried 140g Hornady Match, Sako 140 and experimented with hand loads.
I've found that Reloder 16 works well ( better than the expensive Hornady stuff

The only issue that I have had is when fitted a Timney Trigger. The videos make it look like a 3 min job!
Actually fitting the trigger is an absolute doddle, refitting the lower however is not

The safety selector will not fit into the trigger ( being wise after the event, I looked on 'tinternet and found that other people have had the same problem!)
I tried "polishing" the central area of the selector but have been a bit too energetic, so I'm now looking for an aftermarket selector.
Lesson learnt , take trigger and gun to a less " enthusiastic" gun plumber!
Best, the incompetent Greek