Hi guys and thanks for all of the helpful suggestions so far.
It's probably fair to reveal a bit more about why I asked about undroppable ammo to provide more context; The ultimate goal is to build a serviceable enough "recharger" weapon such as what was in Fallout New Vegas. I'm not really interested in a 1:1 recreation just so much as to get the 'spirit' of that weapon realized.
For the most part, I believe that I've done that: A weapon that generates ammunition when it is in your possession and only to a certain quantity. How quickly the ammunition generates and to what amount are inconsequential and can always be adjusted later. When given the "Never Ending" legendary mod, the weapon acts reasonably close to how a F:NV "recharger" weapon functions. That part of the project, in my view, is complete.
Unfortunately, a by-product of my results is that I now have ammunition in my inventory that can be dropped from the inventory. It's not exactly a game-breaking "bug" but it is an annoying artifact from how the ammunition regeneration process occurs.
I've attempted to neutralize this feature in two ways: Make the ammunition monetarily worthless so that there's no incentive to sell it. And, in the meanwhile, I've utilized a timer for the ammunition generation to also check the inventory to see if the inventory is above a set limit; If it is above that limit, reset it to the maximum limit, thereby "deleting" the excess ammunition (although, now that I think about it, I've envisioned a really neat way to "penalize" the player for having excess ammunition by possibly irradiating the player for every moment that the player has excess inventory... Hmmmm....)
Pardon my lack of understanding with Papyrus but how would one attach a script to an ammunition object? I don't see a place in the ammunition window to attach a script (as opposed to a weapon or miscellaneous object). Thank you.