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.