I sighted in my 300wby mag. last month and was dead onat 100yds (2 inches high, all holes touching). So I went out today and my shots were all over. I was unable to group them, and every time I thought I was on the pattern would change. Could it be my scope, the mounts, the weather,(it was very hot outside)? I left very discouraged, and down 50$ in ammo as well. Could you guys please provide some ideas!! Thanks

i would bet on the scope or mounts or rings.

the hot temps shouldnt have such an effect...should still hold a group even if it was somewhat off from before...

check it out and see if you cant find a loose screw or something.

then if that dont help id have the scope checked. could went bad. ive had it happen. i had one that every time you changed the scope power the crosshairs randomly moved and never moved back..it was all over the place. junk scope though...thats when i quit using junk scopes.

then if the scope checks out id take the rifle to a gunsmith or call the rifle manufacture..

just take YOU(shooting poorly that day possibly or something to that extent?) and the scope/bases/rings out of the equation.

could be a number of things...check them all out and see if you cant find the culprit...good luck

I recently had exactly the same problem with my .300 Weatherby Magnum and it turned out that one of the screws on the scope rings mounthad sheared off. I would check all screws on your scope rings and mounts to be sure they are intact and tight. The screws have a tendency to both break and loosen under the heavy recoil of the .300 WBY Mag.

Caldoc

You didn't say how much you shoot. If its not the scope bases or rings being loose, it could have been just a bad day for you. I consider myself a fairly decent shot but you have to continue to practice. I usually get out every week or at least 3 time a month. I was doing really well up to winter then stopped til the weather broke. The first couple of times I went out you would think I never fired a rifle before. Rifles that were shooting in the 1/2" area were up to 1 1/2" and worse. But now I "got in the zone" again and shooting well. (check the post "more kudos for savage" in the firearms review forum for the target I shot with my 7-08 yesterday.)
My guess is you were just having a bad day. Problem is your ammo is so expensive. Maybe try practicing with something easier on the pocket first.

Is it a wood stock? Could be your stock has picked up some moisture/oil and swelled the wood causing pressure on the bbl.

Just ran into this problem with a new Ruger Hawkeye in .257 roberts. It was actually shifting the action in the stock. Swelled so tight I broke 2 good quality hollowground gunsmith screwdrivers trying to get it out of the stock.

The other advice is great as well. Could be scope mounts. Could be scope, could be you. I have had days that I felt fine and couldn't hit a bull in the butt, let alone the "eye". One way to tell is to let someone else shoot it.

Good Luck

Thanks alot for all the ideas, I'm new here so it is really appreciated to log on and see quality tips from quality hunters, and shooters. I am going to have the scope checked out and replace it if necessary. All the rings and screws seemed to be iron clad at this point. So it has to be the scope I'm using. I am on a budget so my new scope will have to be in the 150-200$ range (like the one I have now). I am going to go for a populal name like Burris, Nikon, or leupold (if I can scrape some change up somewhere). All these things take time so I guess it's good I wasn't drawn for anything!!

Thanks again