My Classic has always shot .500" groups at 50 yds since its 500 round break-in. Now, after 18 months, it has suddenly started acting strangely. She has always liked CCI Standard Velocity. (She likes Wolf Match Target even more, and used to do .375" groups at 50, but I save that stuff for bench matches). The CCI's I have are all the same lot number. Head shots on rabbits was no sweat, and there were very very few blackbirds that lived after my crosshairs landed on them. All of a sudden about a month ago, I started missing. Ok, no problem, punch some paper, I must have bumped something. The groups had opened up to 1.5", with a wandering zero. I broke the gun down, and did a very thorough cleaning. Back to the paper. I am now getting 1.25" groups, with the zero still walking, mostly left and right. I switched scopes, with no improvements. The Wolf ammo falls into .750" groups, but they wander as well. I am going to try a third scope this week. I cannot imagine what is causing this. Any ideas? I have always tightened the action screws as tight as I could get them, and even tried different torque values to no avail. I have tried different brands of ammo and different lot numbers with no benefit. I even tried a pressure point along the barrel in different places. Strangely, that did nothing for the groups -- they stayed the same, just shifted upward a few inches. I believe I have tried everything I have read here, and within my mind. Any ideas and/or suggestions would be greatly appreciated.