You don't have to look back that many years to find gun barrels used as rebar. I helped a neighbor when I was in high school, remove a wall in the house he recently bought, so he could add another bedroom. The house was built right after WWII. I call these post war houses, bomb shelter houses. There were more than a few of these cinder block, and concrete, houses built in my neck of the woods by returning G.I's. This one had every void filled with old gun barrels, wired together, and filled with concrete. The builders father was an old gunsmith, that must have had a truckload of old gun barrels. Some of the barrels we found were big old longrifle barrels.
Hungry Horse