I use AP reels, and have had some problems loading them. Normally it is because of moisture building up inside my changing bag. My reels can be changed from 135 to 120 (as most reels probably), and I found it worked better if I pulled lightly on the edges of the reel. That usually helps.
I use paterson reels (that are similar afaik) and sometimes the film can jam, i first try sharply tapping the reel on a hard surface, and then sort of wiggling the spool edges gently, seems to work. But the main problem with mine was dirt on the bearings that pull the film round, worked much better after I cleaned it with an old toothbrush.
Never had a problem loading 120 onto plastic reels, Paterson or Jobo, do it stood up in the darkroom, once the first couple of inches are on the reel its plain sailing.
Paul.