I have a Browning BAR in 300WSM that has been a real shooter. I took it to the range a few weeks ago to make sure everything was OK for this hunting season. My favorite load of 71gr. Ramshot Hunter and 165gr Nosler Partition shot great. I also shot some rounds that were no longer needed and taking up brass, about 35. I would shoot 3 and let the gun cool completely. My last 9 rounds were R-19, 64, 65 and 67gr with 165 Partitions. These 9 round could be covered with a quarter (no shit). When I got home I took the gun apart and cleaned it real good. Last week I took it to the range just for something to shoot with the others were cooling and WOW what a mess. I was lucky if I could get a group under 2 1/2 inches. I checked the BOSS and it was tight. The loads were from the same session that shot great before. The only thing different was the take down . Any ideas as to what I did to scew this up??

yeh, when you tightened the action into the stock you probably got it in bind.
try loosing and retighten one then the other a little at a time do not over tighten,

Yup...

Once you work-up a load that you are happy with, you never, ever, dismantle the firearm!

"Perfection is the worst enemy of good enough."

Steve,

I'm sure your rifle is just fine, you probably have a screw too tight or something.

I gave up on BARs after I had one do similar but much worse. It was a grouper at one time and then all of the sudden started shooting 6" groups at 100 yards. Imediately thought it was the scope. Tried 3 other scopes, checked mounts, tried several diff. loads, disasembled and cleaned thoroughly and it still shot buckshot like patterns. Got rid of it and added another bolt to the collection. The Autos just have too many moving parts for a rifle IMO. A bolt is just so much simpler and easier to modify.

Reloader