"The dreaded Marlin jam"
I am a big fan of Marlin lever-action rifles/carbines. I own several, and shoot them regularly. I have read of "the dreaded Marlin jam" a number of times, and experienced it once many years ago. That time, I just took the gun apart, cleaned it, and put it back together, and everything was fine. I was out shooting with a buddy this morning and my Marlin 1894 .357 Magnum locked up with the lever at full extension, and steadfastly refused to budge, no matter how hard I tried to force it. I brought it home, expecting to have to take it apart in order to "make it better". Before I did, I tried a few more times to get it to close, no luck. Then, just for giggles, I reached up under the bolt and brought the hammer all the way back, and then let it go back to full-cock. The action closed easily, and functioned normally after that.
"The dreaded Marlin jam"
I own several Marlins and have never experienced that jam, even in rapid SASS shooting. Now, my 1889 Marlins in 32-20 would sometime give me a double feed jam but that is due to worn tips on the lifters not keeping the next round in the mag tube, and hasn't happened since I had Andy Horvath fix 'em.