It's a toss up. I bought a brand new Model 94 Winchester in 1994. It was one of the last holdovers before the "new" crossbolt safety Model 94 came out. It was in .30-30 and this gun could not shoot. No matter what my Uncle and I tried, this gun couldn't hit water if I threw it out of a boat. My Uncle had an identical Model 94, bought at the same store are the same time, he still owns that one and that gun was more accurate than most of the Model 94's I have seen.
The other would have been the new Marlin 1894 FG in .41 Magnum. This was just before Remington bought the company. Got it from a gun shop, took it to the range, and it wouldn't feed handloads, factory ammo, nothing. Everything would bind up, so I sent it back to Marlin, a week later, it came back, and it would only feed about half of the time.
Both of those guns were sold in short order.
The runner up for them had to be a new Marlin 1895 .45-70 with the 22-inch barrel. Always wanted one, bought it, took it to the range, shot consistently 3-4 inches to the left at 25 yards. Adjusted the sights as far as I could get them, got maybe another inch closer. Put a Skinner sight on it, still couldn't get it close. Called Marlin, this was during the transition, the gun was a pre-Remington made, but it was when Remington bought them, couldn't get a straight answer from anyone there about repairing it. So I got rid of it. Sure I could have put a scope on it, but I didn't want a scope on the gun.