Part of the problem here is me spltting off the post from the original. If you go back an look at the "Dismal at Best" post, you will get a better idea of my trials. Let's face it, folks get tired of seeing the same post. I posted because I thought it might give others a good history of the troubleshooting process on a particularly difficult rifle. I have been chambering, throating, crowning, and reading chamber casts for over 20 years. I have a rough idea of what makes a target rifle tick and all these concerns are non-issues on this rifle. Rather, I am quite impressed with the apparent out of the box quality of this rifle.
I am not too proud to say that I have very little experience with these H&R singles, which do present their own uniques set of issues. This is where I am relying on you guys to help troubleshoot. I have picked up several EXCELLENT ideas from this forum. After review yesterday, I feel that part of the issue was the adjustable scope mount. A loose mount would certainly contribute to the randomness of the groupings. Note there is not a whole lot of stringing going on. One point several of you keep missing is that this is a 32" Buffalo Classic and I am using 350 grain cast bullets which SHOULD shoot excellent from a 1:20 twist. In a previous post I indicated that I had shot two groups of factory 300's with poor results. I will put the iron sights back on in hopes of getting a chance to shoot some more factory 300's this weekend. I'll let you know how that turns out.
Merry Christmas and happy shooting to all!