I wander how well this works on some of those hard to split woods like elm. Around here we call this splitting wood. Chopping is cutting to length with an ax.
I learned to really split wood from a blacksmith that lived in Potosi Mo named Tom Clark. Tom took a single bit ax and welded a 1.5 x 1.5 block on the back of the ax head and ground it to the contour of the original head. This added a weight that gave torsion to your ax head. TO use the ax you held it with the head canted about 30 degrees to one side rather than straight up and down. Tom's method made splitting wood very efficient and fast. Tom use to do local demos where he would take on a team of men using he latest miracle wood splitting gizmo. He never lost a contest. By time they got through a rank of wood he was usually way ahead.
I don't' have one of Tom's custom axes made for this but I have found that a double bitted ax gives almost as good results if held the same way. I'm not as fast as Tom was at it but it is the fastest way I can split wood myself. There is a technique to it but once you get the hang of it it is easy and a lot less physically stressful than using a splitting maul or wedges.
I don't know how to embed a video but I did find a vid on you tube of Tom splitting with his custom ax. Even hard to split hardwoods with interlocking grains would split using his method.
Tom clark splitting wood
Here's another one.
Tom splitting 2