Although the Ross Mk3 can be re-assembled wrong, you have to be a total idiot to do it.
The big problem with the Ross is that it has a straight-pull bolt, where the sleeve and the bolt head are connected via intermeshing helical grooves. When dirt gets into these grooves, the bolt becomes VERY difficult to operate, and after a while requires to be beaten open with a lump of wood or a boot. Look at the animation in Praetorian’s signature - that’s a Ross being fired & then beaten open.
The Ross was also a design born of the “Bisley” school of thought that an individual infatryman should be able to engage a point target (i.e. an enemy infantaryman) at 1000 yards. Thus, there are many features on the rifle that are more suited to target shooting (Ross was a long-range competition shooter, IIRC): the barrel is too long, the rifle is too heavy, and the sights are overly complicated with the battle sight set at to long a range. It is, indeed, extremely accurate. There are a few other peculiarities with the rifle as well: the charger guide is offset, so the clip is positioned at an angle, and is slightly tricky to push the rounds out of. The magazine is also a single-stack sheet metal affair which protrudes from the bottom of the stock and can get damaged.
The straight-pull action is extremely fast when it’s working, but when it jams, the rifle’s useless. Once this was discovered, the Canadians were re-armed with the SMLE as quickly as possible.