Most shops are to greedy, they will sit on a gun for years to make $100, better to make $25-$50 and have the sell that week.
A guy I went to HS with owned a gun/pawnshop for several years. Starting in January, after deer season ended, he would sell just about any deer rifle at his cost. That put money in his till to pawn to people @ 20% interest/month. He knew that he could sell a rifle for $300 in September, but the $200 he got for it in January would bring in $360 ($40/month) in profits off interest between January and September.
Handguns and non-hunting rifles sold at about the same pace year-round so he wasn't quite as quick to come down in price on those.