I have a Ruger American rifle in 30-06 for two years now.  It been a good rifle for the last two deer seasons.  1-1/2" to 2" groups (100yds) from my reloaded ammo (which I may be able to do better but I'm happy with that). Now in saying that that was the last two deer season.  

Now this season (in the last two weeks) I've shot about 40 RDS through it and can't do better than a 5" group at 100yds.  I've check everything rings, screws and scope.  I even tried two different scopes and two different sets of rings.  I'm using the same ammo as the last two seasons and have tried factory ammo.  Same results.  I've cleaned the crap out of it too.  

Has anyone ever pulled out a rifle and it all the sudden wouldn't group?  Can a hot barrel loose that much accuracy at 100yds?  After one shot the barrel is really warm.

Maybe check the action screws.  Are they all tight?

shoot it then look and see if stock is touching barrel.
Mine did. massive acuarcy loss

Wooden stock? Check for splits or other damage to the bedding.

If it still won't group call Ruger. You have a warranty and there's no shame in using it.

AJ

I'm going to shoot it again this week some time  and try a few things listed here.  Thanks.

I think these rifles use the same set up as savage rifles, a barrel nut. Is it possible the barrel nut is loose on yours?


I would probably call ruger if it were me, they have excellent CS.

You said you cleaned it, but maybe it is copper fouled?

I think it was multiple things that in was doing wrong and it did stop liking the rounds ive been using (Hornady btsp interlocks).  I swiched to Hornady flat base sp interlocks.  I was shooting to much on a hot day so the barrel was getting really hot and was shooting from a sand bag rest so the forend was pushing onto the barrel.

It shoots a lot better now (1.5" groups at 100 now).