It is some hard stuff for sure. Im thinking your bitternut may be a younger shagbark. Ill get a pic of the bitternut in my woods later.
I think you are right. According to this pic it's a shagbark because the nuts are lumpy and not smooth just like this pic below.
I still have trouble identifying hickories by bark alone, unless it's a pignut or a mature shagbark. It's not as pronounced in this picture, but the way I recognize shagbark nuts are the seams where the 4 quadrants of the husk meet. This translates to 4 distinct ridges on the nut shell itself inside. They're delicious BTW I saved a bunch in the fall that I was snacking on well into the winter.
Here's a few pics of different size Shagbark trees, with a trench shovel just for size and bark comparison, and a nut. Shagbark's are my favorite tree to look at. I should collect some nuts too, just to try them.
And God splits those vertical trees with lightning! Man, having no lightning at his disposal, fells the tree horizontal and correctly orients his splitter the same way to split the wood. Age old arguments from stone age cavemen til now!
The milk crate and Saber Tooth Tiger skin cushion with tail attached are my respectful nods to Backwoods Savage. Call it "artistic license"!
Some pics from today in my woods. Pignut. Smoother bark...i think bitternut but not 100% sure. Younger shagbark Twins, i think both pignut, but one on left has smoother bark. While out today i passed this nice shagbark. The tree nerd in me had to back up and snap a pic.