I've done the math, and just finished a long burn test that surpassed 3 days. Time to admit that BK has competition in the long burn department. BK still makes it easier with the thermostat of course.
The 14 hour rating... I did not ask Woodstock what that rating was for, did you? Perhaps that is to heat the rated size home (2200sqft) on a January day in New Hampshire. I do not know, and it doesn't matter to me if they change it or not. I would however say that about 14 hours sounds about right for a regular ol secondary burn.
I may try to put a flue damper in to see if it can even go longer, plus I could fit a bit more fuel in it still. But after you hit 40 some hours I'm not too worried a few hours give or take! That is with compressed sawdust bricks, I'm not sure of its capability with cordwood yet, but likely much less than the 3 day burn I just did.
You bet your buns bk has some competition. Woodstock is nipping right on their heels and even passes them in some areas. 10-14 hours is the maximum burn time as specified by Woodstock. I have high regard for their word. Much more so than the mainstream stoves.
Good job tweaking the stove for burn times. Magnets, etc. We know there's more than 14 hours in a load if you can just slow it down.