Around here full chisel is square ground (that's where the full comes in).
Semi-chisel is round ground, square tooth (and the most common in usage).
Chipper is round, round. Slower but stays sharp longer (lot of homeowner small saws).
My line of thinking too, and like you said, maybe a territory loacation thing. A full chisel to me, taught by fallers, was always square ground, it was not full anymore once round filed. We round and square file both. Anyone who want's to learn the differenece, can see when you corner into a cut, especially on a humbolt. Much harder rounded, than square, you lose that lower corner when round filed, making corner cuts more difficult. Good call! I hear they now have a round filed chisel type, new to me anyway here, but to me as well that is not full chisel either. It is round filed chisel, which is semi right? Or similar. I agree no way it could be full with only the corner square, and not a square lower corner as well. I know the joke used to be us west coast guys and the big bars and full wraps a skip chains. But land of timber fallers and big wood, until someone has had to square from corner to corner, meet cuts on tress the girth of a truck, reach overhead jack a tree up hill, with little area to escape, and use climbing gear to ascend down a tree, just to buck it, as the ground is so steep. Some things are hard to translate, or explain:msp_thumbup: O.P it is only difficult in dirty wood if you lose a corner, you are done. But I don't care what king of chain if you dull it, you don't cut anymore. Like mentioned by 2dogs, and others, not as good in dirty conditions, but I don't cut much dirty wood. For a production firewood cutter, certainly one who has to skid logs, then buck into rounds, that is just tough all around.