460 Mystery

[River Runner]

I have a mysterious grouping issue with my 460 XVR perf. cnt. 14" barreled revolver.
I installed a Leupold VX3 handgun scope on it and it shot like a dream with hand loads. 47grs. 296 or H110, with 240 grn. Hrndy. mag. bullets. The turrets on this scope are not user friendly so I sent it back and had M1 tactical turrets installed, the same as on the older Mark 4's. Same everything except the turrets and the gun won't group better than 8 to 10" at 100 yds. and I can barely stay on the paper at 200. Originally before the turret change I was doing consistent 5" groups at 300. Everything was shot from a rest I built and it was grouping extremely well at that time.
I sent the scope by to Leupold with a very lengthy explanation and it came back with no malfunction, but the grouping is horrible again, no improvement at all. The scope has a death grip on it and it's not moving on the rail or in the rings.
My money is still on a screwed up scope since it was the only variable, but Leu. says it good, so if anyone has some ideas, my listening ear is tuned to the frequency of your voice.
Thanks,
R.R.

[Kernel Crittenden]

Try another scope. See if the groups improve. If so, you know it's a scope problem. Even a dot sight would do better than 8 - 10 inches at 100 yds. Heck, even open sights, supported in SA, could do better.