When we were kids, 18 or so and invincible, a few of us had Belgian Browning Auto-5s in 3" Mag. When we were waiting for the Canada geese to come in we would get bored. So, someone wanted to see if they could cut a standalone fence post down with their Winchester XX Magnum lead loads. That morphed into someone having the bright idea of taking out their pocketknife and scoring the shell about 1/2" above the brass. When the load was shot it cut that fence post in half at about 10 yards. Nothing came out of the gun except the brass. We all did it a few times with no negative results. But, now that I know I'm not invincible I would never try that stunt again.
