Shot the rifle a month ago with floated mag box and new torque settings. With my old accuracy load the rifle went from 1.136" 5-shot group @ 100 yards to 2.179" 5-shot group @ 100 yards.
Oops!
I should have followed the sage advice of only messing with one thing at a time so I knew for certain what caused the issue. Easy enough to go back to previous torque settings though, so I backed the rear action screw back down to 15 in/lbs. I didn't get to shoot it again until last Friday.
The crappy part was I only had three shots left of my accuracy load. 1.067" 3-shot group @ 100 yards. Wish I had a full 5 shots to get a fair comparison. Shots 4&5 could easily make it a 1.8" group as well as having them land within it. Oh well, no way to tell how it would have played out.
All is not lost though. I still have some bullets from that same box (160g Sierra GameKing SBT) and the brass is the same lot as before. The newer lot of powder is ~5% faster than the one from 6 years ago and I went from the Winchester WLR to the Federal 215 mag primer. And of course the aforementioned return to 15 in/lbs (from 30 in/lbs) on the rear action screw.
The results:
5-shot group @ 100 yards: 1.059"
Velocity: 3,007 fps (114 fps gain over old accuracy load)
Extreme Spread: 5 fps (reduced by 40 fps over old accuracy load)
Standard Deviation: 2 fps (reduced by 3 fps over old accuracy load)
Seems I have a new accuracy load.
Guess my rifle doesn't like the rear screw very tight, as per Rugers recommendations.
Now I need to see if my other established loads fell apart.
