I'm not sure why this post has really caused so much discussion. Not only do NEF/H&R chamber for only non-magnum rounds for a good reason, but there is a general consensus world wide that break open actions, be they single shots, double rifles, drilling or cape guns, aren't as strong as bolt actions or falling block actions.
Why we should argue about whether it's safe to chamber Handi-rifles in WSM or big magnum cartridges seems ridiculous when NEF takes the road of least risk. Of course the barrel lugs get worn, of course there seems to be issues with opening on discharge if we make it do what it wasn't designed to do. Save up for a Ruger No.1 if you must have a magnum.
In my personal opinion, and it is just an opinion, properly used NEF makes chambers for cartridges you can use to hunt almost all game. I've seen so many posts where guys take elk or moose with a 30-06 or a 45-70 and the handi-rifle hasn't caused problems there. To quote another post I read a while back "It groups better than I can shoot!" Perhaps we should worry more about our own abilities & less about how our rifle won't winkle a bottle top at 700 yards. I know this is an exageration but I'm sure you see my point.