I took two of my hunting rifles I have not used for over 25 years to the range yesterday to get new scopes on paper, a 30-06 and 300 Win Mag. I had four boxes of old Winchester factory ammo (two of each cartridge), which had near identical appearances. I accidentally chambered a 30-06 round in the Sako 300 Win Mag. It sprayed powder on my face and cracked the stock at the pistol grip. if I had not been wearing safety glasses I might be blind right now. I feel lucky and am very thankful for being ok (other than my face looks funny right now) and also grateful for learning a valuable lesson...I will never put two different cartridges on the bench at the same time again. I wonder about the state of the action and barrel. The bolt cycles fine and the bolt face is not burnt or damaged. Using a Lyman borescope I can not see any obvious damage in the chamber, throat or barrel. Is there anything I should look for specifically? Should I have the action and barrel magnafluxed to make sure it is not harboring a crack somewhere? I suppose I could find a clamping type rifle rest and test fire it several times with a long string. I welcome inputs from the gunsmiths here.