I’ve never owned one, but I own a book called “Winchesters”, as I recall the problem was the rounds themselves, stored in the magazine. This is still a problem today, or can be. If a round nose bullet is butting against the primer of an adjacent cartridge, a hard enough drop or jolt can possibly set it off. Then the rest of them go off too. Probably more annoyance than a danger, but I dunno.
Well, surely someone wants to get rid of one then, lol.
The solution is to buy Cowboy ammo, with a round nose flat point (RNFP) bullet. Made by many companies... Ultramax, Black Hills, HSM and others. For higher porformance (say out of a bit more modern rifle like a Marlin 1894, Hornady makes the LeveRevolution that has a soft polymer pointed tip.
Not round nose bullets, those are fine in tube mags, or flat nose. it’s the pointy ones you can’t use, although now they have them with soft plastic points that are safe and shoot a lot farther than round or flat.