As a general rule, Saturday is a good time to sell, as the dealers buy thinking they will have time to move it there. Sunday afternoon is a good time to buy because the sellers don't want to pack any more hardware home than they have to. They would rather have the cash. I've seen guys that go to the show, buy guns from people walking in, walk the show and sell them themselves, and repeat the process throughout the show. I've sold several guns right at the front inspection tables. Though, most of the time, those guys are looking for the Rube, who will take $50.00 for grand dads's old Remington Rand .45. (i'm not that gullible, I got $100.00 for mine..:).
The caveat here is that if you spot a rare item, or one that you really want on Saturday, I wouldn't wait till sunday to try and buy it. It will probably be gone. I've found items at the front tables I wanted, and decided to wait till I walked the show before I bought anything. I went back to the tables where I saw what I wanted, and it was gone. And I've had the oposite happen. Buy something at the front, and find a better deal further back into the show. So it's really hard to give a precise answer here. I do try to go on saturday's to sell, and Sunday's to buy. As far as ammo and accessories go, I've found better deals on the net than at the shows. But if you are in a hurry, then it's cash and carry at the shows. I prefer to buy my guns face to face. I don't care much for doing paperwork, so I try to deal with individuals, or dealers selling "Private" stock.
Gun shows are fun, and a good place to do hands on research before you buy.
Enjoy them while you still can.
Rich