UPDATE: I was finally able to remove the jammed (and disfigured) pellet.
This picture shows the rotary cartridge (from the User Manual) being inserted behind the barrel. The dark-colored section of the magazine holds the pellets, while the light-colored section (transparent, actually) rotates so as to allow manual insertion of the pellets. So these two sections rest on each other with the light-colored section rotating over the dark-colored section.
In any event, it was at this juncture of the two sections, as depicted by the red arrow, that I first took a coping saw, and then a hacksaw, to cut through the axis of these two sections. Once I cut through that point, the light-colored section was able to be pulled out and away, at which point a single pellet fell out. I was then able to gain some wiggle room and subsequently remove the bulk of the magazine, with pellets. I then blew compressed air in and around the area behind the barrel, so as to ensure as best I could that there was no foreign matter.
To me, this seemed the least-invasive tactic. That is to say, it was least likely to damage the gun, sacrificing only the rotary magazine, which is replaceable at minimal cost.
I will add that I did remove the scope for this undertaking.
So now it's back to square one: mount the scope, adjust it, ensure the gun operates appropriately and safely, and try NOT to do this again.
My thanks to everyone for their suggestions, thoughts and good wishes.
P.S. I plan to issue another update regardless if the outcome from here on out is a good one or a bad one.
But I will say that in my particular case, it was user failure, not equipment. Still, a word to the wise (well, maybe at least wiseR). 
