Hi @StockSavage
As long as you rotate the bones to match what REAL LIFE arms look like they shouldnt look out of shape unless you bend way past what a person is capable.
Check your roattions look at you own arm. Also in the arms there are some twist bones. Check those out that they are correctly aligned so there is no distortion.
Thats said i have a problem myself with manny animations. I made one for a pistol aim but it looks nothing like in game what it does in the animation.
Maybe you have the same issue?