I agree with cayugad.That load should have made a clean kill even through a tough shoulder. I only hunt with patched round balls and have had excellent results over the years. I have shot many deer through the shoulders with a varitey of calibers and always had clean kills.

The only time that I have had a problem with penetration happened in 2005. I was shooting a 58 caliber loaded with PRB pushed by 130gr of GOEX 3-f. I had previously cronographed this load the the range at more that 1800 fps. It worked perfectly at the range, shooting pretty flat from 25-100 yards.

With this load I shot a buck in the shoulder@ 25 yards and ended up blood trailing it for more that 250 yards. When I caught up with the deer I shot it through the neck to kill it.
When field dressing it I noticed that one lobe of its right lung was destroyed and the left lung was untouched. I also noticed that the exit wound in the neck was a slit about the size of a knife blade.

The man who butchered my deer returned my bullet telling me that he found it just under the right shoulder. It had flattened to the diameter of a quarter and not much thicker. I can only surmise that flying bone fragments from the shoulder did the damage to the right lung. I have since reduced my load to 90gr f 3-f and have had complete success with full penetration.

Getting back to your load. I see no reason that you should not have at least penetrated both lungs. I have successfully used that same load in many of my 50 caliber rifles over the years. I have always used GOEX black powder.

Did you recover the ball? If so, what did it look like? Studying the shape of recovered ball can sometimes give you answers as to how your load is performing.