Worked in a Woolco sporting goods department about 45 years ago. We sold guns, including Marlin 336s. Working the counter one night when this customer came in with a rifle he'd bought a couple of days earlier, pissed to the max. Seems one of my fellow sales clerks had sold him a .35 Remington and a box of .30-30s and neither of them realized that just because it was a 336 doesn't mean it's a .30-30. Sure enough, one round fed, fired and as you might imagine, split the case and released some gasses out of the receiver. We refunded the guy's money.
My boss, who ran the department and was somewhat gun savvy, looked at the rifle. decided it wasn't harmed in any way, ran a patch down the barrel and put it back on the shelf. We also did a bit of remedial education with my fellow sales clerk, who was amazed to find that 336s came in more than one chambering.
