Used them for 60+ years and I don't remember them not killing what they hit. I will admit though that I am not a long ranger. I think nearly all of my shots were within 200 yards. when I pulled the trigger I was pretty certain it was a kill shot.
Good job, The only thing wrong with your set up is there is no place for your butt. Most of us old guys would put the wolf behind the saddle, put the butt of the gun up close the the swell of the saddle, put the barrel of the gun under the fender and our old butt in the saddle.