Most 16 shells available without $pecial $$$ order are for more modern guns with standardized long chambers.
I second the motion of finding a 12-12/‘06. Ammunition will be more easily acquired and the gun will be more usable. The only drawback is that it will be larger and therefore heavier. Drilling’s are not guns you pack on hikes though so heavy doesn’t mean as much for a range toy as it does a working gun.
I'm at a loss as to where you get your info, every 16ga. length shell is easily available on line, in several different loadings. I bought a case of 2-1/2" light loads to shoot through an old hammer 16ga drilling that I own, (RST brand)
They just aren't THAT expensive, and yes I do reload for 16ga...
As for hiking with my drilling, are you kidding me? I bet I've "packed" my drilling hundreds of miles. I mean what good is having such a fantastic hunting tool, and then not hunting with it?
Like I said, Mine weighs right at 7 pounds, and I've carried it on every kind of hunt I've been on, from moose and bear,
on down to deer pheasant's and other small game.
I even carried it when walking a trap line, you never know what you will happen onto, like this fox I shot with the 22 bbl.,
These days, I hardly carry anything else....
IF, you end up with a heavy drilling, that's the fault of the buyer, for making that choice. Krieghoff makes some nice drillings yet, today...
DM