Where is the hole? If near the muzzle it is no more than a early proprorted gun. If near the hand then I would not shoot it without a set of Companion tubes in it. Fingers are real important to good follow through.
Repairs can be made. I have seen them done with brazing, welding and the patch method mentioned in other post. A good micro welder should be able to do the job. Repairing a pin hole near the choke area may not be that hard to do. But I would worry about how many other other weak areas are present but not seen.
I had a set of twist barrels that had a leak that went into the area between the barrels about three inches from the chokes. Gas escaped out a weep hole under the fore arm. When I took the fore arm off you would see powder residue. It took me an hour to find the crack area. The barrels rang like a church bell but had a crack that was almost an inch long. Looked like the idiot who reamed the chokes out either gouged the barrel, the weld or put too much pressure and found a weak area. Then he honed the barrels and the crack was almost impossible to see. Do a bubble test to find leaks.
