Hi everyone, I am new to the forum here and new to Mossberg rifles in general, although I have been around Mossberg shotguns for the last 15 years. I recently purchased a used Mossberg 100 atr with a synthetic stock in 308 in part because of the great reviews I have read, and also because I liked the way it looked and felt. After several trips to the range, 4 different brands of ammo, and replacing the scope with a brand new Vortex scope, the best I can do with this gun is between 5" and 8" (100 yards) groups regardless of scope or ammo. I know this is not a common problem with this rifle because I cant find any complaints of accuracy problems with this rifle anywhere on the web. I dont think it is my shooting because I shoot sub 1/2" groups with my savage axis at the same distance with factory ammo. I am not necessarily expecting sub 1/2 inch groups out of this gun, but I don't think its unreasonable to think it should shoot 1 1/2" groups with its preferred ammo although I believe most people are getting 1" groups or better with this set up. I am hoping there is something stupid that I have overlooked that I could fix myself. I did take the stock off to look for something out of place and I didnt find anything real obvious. I tightened up the action screws, but I did not torque them properly. One of the threads on the rear action screw seemed to slip on me at one point so I took it back out to examine it and saw no signs of stripping or cross threading. My groups are totally inconsistent, they do not "walk" from one point to another, but move all over the place. I will have some groups that are totally vertical, followed by groups that are vertical and several inches off on windage. I have tried allowing adequate time for the barrel to cool down between shots, 15 min. between each shot, and all the results are the same. At this point I am thinking it could be the mounts and rings, although they seem pretty sturdy and I have tightened them up as well, or something to do with the action screws, or the barrel. Any thoughts? Thanks in advance for any replies.