Shimming the barrel only you may (likely) have induced stress the rifle didn't like.
Take that business card and put it under the front of the receiver and the rear tang to lift the action out of the stock a smidge, that brings the barrel with it and doesn't stress the action.
Business cards are kind of a bother to keep in place so a better way is to cut appropriate sized pieces of electrical tape instead, they will stick where you put them. Put one on top of the other until you get the thickness needed. Main thing is to put the same amount under the front and rear of the action to lift it straight up.
Some folks consider a barrel free floated when you can slide a dollar bill along the barrel from forend to action but I like to really free float them so lift the barrel up until two or even three dollar bills slide easily (inflation, you know, it takes three dollars to do what one used to
).
