BigTim,
Nearly everyone else was blaming ammo. However, I find it unlikely that ammo would cause that big a difference, so I went with the next likely cause. (And, hey, like I said in my post, its not the Buckmark that is causing my groups at 85+ yards to be like they are, its me. I'm certain that others could get better results.)
You seem to have an interesting problem. It appears from your posts that you believe the pistol, the ammo, and you to be capable of better accuracy.
I still think the fastest way to eliminate the shooter is to have a couple of others shoot it.
As I said earlier, I doubt its the ammo causing that MUCH error. Certainly ammo plays a role in accuracy, but not normally that much error with name brand ammo.
This leaves the firearm.
What kind of accuracy can you get with open sights?
Muleshoe may be right on when he said, "Maybe its in the scope?"
I still don't think ammo is going to solve the problem. I think you are going to have to look for other solutions.
Sprig