Collectors have a focus. Accumulators do not. Most people who consider themselves "collectors" are not. They are merely accumulators who want to see what it's like to own, shoot, and show off shotguns, rifles, or handguns that have some appeal for them. They have no focus on gauge, caliber, grade, uniqueness, or rarity. They may buy a certain model or brand, but no real hard specifics are used otherwise.
Bob Cash's Model 21's are perfect examples of an accumulation. No real criteria were used other than a desire to acquire a certain gun because it was neat, it looked good, he like it, and would be a good version for "x" usage. Not judging, just saying.
JR
Really? We can only be collectors if we follow your criteria. Is that it? How about the focus is SxS shot guns? Is that too broad to be allowed under your rules? Maybe German or French SxS shotguns? Or SxS shotguns made before the Great War? Would that qualify?
The ego required to tell us what constitutes "collecting" is staggering. And not in a good way.
The problem, John, is that the words "collector" and "collecting" actually have a very broad meaning. You can't narrow it's definition for all of us to suit what you imagine it means...for you. I suspect you need to find a different word...or add some modifiers to make your meaning clear.