'Completed sales' on any of the auction sites are interesting, to be sure - they give one an idea of a single snapshot in time when several individuals wanted 'that' particular piece, and bid one another up until there was a 'winner' of the competition.
It's a good way to reach a lot of people and sell things, but it's only a general guide.
Right this minute, folks are strapped for cash, thanks to Christmas bills coming due, and that means they sell their 'stuff' more reasonably.
What that means to a prospective buyer is that he's got to have feelers out all the time, and he's got to cast a wide net - and trolling gun shows, pawn shops, 'gun libraries' and the internet aren't going to be a part of that.
I've done this a long time, now - folks know what I collect, so I get calls because I'm fair, appreciative, pay fair prices and don't 'ever' try to screw anyone, ever - it's the personal touch that pays off.
A small ad can pay off, too - but use a carefully worded one - too many are immediate indicators that the prospective buyer is a vacuum wanting to Hoover up, so 'he' can re-sell, or 'flip'.