Actually I've shot many rounds of various calibers into steel plates as thick as 1". Not withstanding my 50 BMG, the other calibers wouldn't penetrate but would make huge craters with lots of neat stuff going on. The last time I shot into a thick steel plate was with my Swift. I only got back about 40' and shot a round approaching 4000 fps ( don't try this ) The bullet hit the steel, and then I noticed something immediately flying back at me, striking me in the lip. My lip was bleeding, turned black and blue.....and hurt like hell. Turns out ( you guessed it ) the bullet hit the plate and there was so much energy it bounced back and struck me. That was a good lesson, a very good lesson.
I for one am interested in your experiment with the seven rounds. Can you explain why the rounds all came out ? What was the secret that you knew before you shot it ? Needless to say, you must have know the outcome before firing the gun.....or did you.