Don't shoot round nosed/pointy bullets in any lever action. (errr any tube fed gun, I know there are magazine fed levers)
Round nose bullets are ok, in tube magazine rifles if they are blunt (and close in size or larger than the primer) and made of a soft material, such as LEAD. Pointed bullets, and "pointed round nose" (such as many 9mm Luger bullets) with hard jackets are BAD. pointed bullets with soft tips like the Hornady plastic tips lever gun ammo are ok.
And, just FYI there was a rifle, a tube fed pump specifically made for pointed bullets. The Remington model 14 and later 141. Made for the pointed bullets used in .25, .30, .32, and .35 Rem cartridges. The tube mags were made so that the bullet tips were in a "spiral" arrangement and did not contact the primer of the round ahead of them.
I've never had a Marlin Jam, guess I don't shoot them enough.
What I have had, with the 1894 carbine in .357 is a jam feeding SWC bullets. Under the right conditions, the round "bounces" a little bit on the lifter and the sharp shoulder of the SWC bullet catches on the edge of the chamber.
If this happens, DO NOT force the lever shut, simply pop it forward a little, and the jammed round will fall into its proper place when the pressure from the bolt is removed. THEN you can close the action normally.
If you intend to hunt with the .357 carbine, you MUST pay attention to the bullets you use. Expanding bullets are made to expand within a certain range of velocity, in a controlled fashion. A bullet meant to expand at pistol velocity can be seriously overdriven in a carbine which can add 500fps to the speed over a pistol. 125gr JHP are notorious for hyper expansion when driven up to the 2200fps possible from the carbine. 158gr JSP less so, they are heavier constructed and can't be driven as fast as the 125s.
The little carbines are great guns. Light and handy, and with magnums more powerful than you might think with very low recoil. Don't expect an MOA shooter, the sights are coarse and so are the triggers. Fun plinkers and pest guns, and even good for deer at closer ranges.
I've had 2 in .357, gave my first one to my father in law, who fell in love with it, despite him not being a hunter or shooter. For him, it was perfect for travel in his camper. Gave him a good weapon, and avoided all legal hassles in different states (and Canada) because it wasn't a handgun.
The only real gripe I've ever had with them is that little squared "loop" on the lever isn't quite big enough for all my fat fingers comfort. A small matter, really.
As to the "hottest magnum loads" the Marlins are more than strong enough for anything you will buy from a factory. They aren't "bank vaults" like a Ruger No.1 and you can make handloads that are too hot for them, but any ammo you buy off the shelf will be fine. (and so will any SANE handload
)