In the immortal words of my friend, "look at that back fat jiggle!".
In the first video it's hard to tell, but the second video its more obvious, these cartridges have fairly heavy recoil. They don't hurt to shoot but they strain the muscles on your back. My limit is 4 shots in a sitting, beyond that and I will have muscle pain in my upper back for most of the following week.
I'm sure many of you will notice that I did not do well with these first two shots. The first video was my first shot and the second video was the second shot. However, after these videos were made, I loaded up two more cartridges and put them down range to confirm the load was not suitable. The right barrel shoots way left while the left barrel shoots far right.
I will try 280gr of black powder next time. But I'm not concerned as my smokeless load has already proved to be accurate enough for hunting.
My neighbor (who recorded the shooting) also took two shots with round balls over 10 drams (275gr) of black powder and one shot with my 1200gr smokeless load, did very well! All three of his shots would have been fatal to a buffalo at our 48 yard distance (the entire length of my yard).