We were testing Minnow's ATD50 at Bass Pro a while back and broke 100# pline with a straight pull and the drag buttoned down. It still had great free spool but I wouldn't recommend fishing that way. I remember seeing some posts on Allcoast a few years back claiming at extreme drag setting a C clips would break as some sort of fail-safe and put the reel out of commission.
found it.
http://www.allcoastsportfishing.com/...ng_type=search