Hi, Master Blaster and guys.
MB, that is not the result I would expect from light wadcutter loads. Maybe the first round had no powder while the second had a double charge (very possible when diddling with a progressive loader).
Barrel damage from a stuck bullet depends also on where the stuck bullet is. If it is directly in front of, and in contact with, the bullet being fired, both bullets will usually exit with no damage. But if the stuck bullet is some way up the barrel, the bullet being fired has time to build up velocity and energy. When it is stopped or slowed by the stuck bullet, the built up kinetic energy has to go somewhere. The result is high heat and usually a bulged barrel. Even if the barrel is apparently undamaged, it may have been weakened in that spot.
Jim