I had the 800 basic, the 12 fps version, and the damn thing had horrible POI shifts!
What I was told is because these actions are a two piece design that this causes shifts. I was also told that with the right one piece base, which bridges the gap over the action loading port, that the shifts are reduced, I tried that too, nope didn't much help.
I know of some successful FT shooters that had some one piece actions machined up for their P70's, similar action I believe, both those rifles shoot exceptionally well.
It's too bad because everything else about these 800's is awesome!
My advise is NO don't convert it.
By far the most annoying and frustrating thing about AG's to me is POI SHIFTS!!!!!!!!!!!!!!!!!!!!!!!!!!!!