We all have to experiment from time to time, now a .270 in a 30-30, I'll leave that to other folks. I did shoot a few .40 S&W rounds through a G20 10mm once, just to see and it went well. Put them all in the center of my target and no damage to the gun that I could observe.
I've also had some lil homemade cannons that might not have been the wisest to fool around with but I was in my late teens and was bored so...... still have all my digits. Not like a neighbor down the road who had to be airlifted because he liked to make pipe bombs and set em off. Same guy who walked around town for about a month with a huge bandage/cast arrangement that looked like a giant pamper because he was drunk as a skunk and walked into his house, dropped trou and confused his piping hot wood stove with the john, 3rd degree burns and a few skin graphs later......