Welcome to the forum. I think as Taylor says, it is not a good idea to use it. If it was important to you to be able to soot it send it to Bobby Hoyt to have it bored out and sleeved to the caliber of choice and your back in business other wise just buy a new barrel for your project its going to cost about the same either way.
I ended up with one of my barrels on a project with a screw hole breaking through into the bore. Fortunately it was the very end of the muzzle and I just cut off the area affected and re did the hole being more careful not to break off the tap.
