Hello, I have a .300 wby mag that was just returned to me from a friend that hunts (I dont). With the gun he returned a few shells with it. Upon inspection it appears that he is/was using .300 win mag shells in my wby. I am asking if the .300 wim mag shells could have hurt my wby. I know that the wby is a larger shell than the win so the casing should have expanded to match the chamber. I dont have any way to look into the bbl where the shell would have expanded but if needed I can take it to the local gunsmith. The person will never be using the gun again. Thanks for the help.