#4 loose front sight assembly

[Patrick Chadwick]

My AIA Enfield is right to left though. Dunno why they changed that from the real mccoy.

Maybe the guys who make the AIAs are all left handed shooters?

Seriously, although I would not claim it to be a rule, it is definitely a tendency, and can be observed, for instance in Mausers.
I think it comes about like this: hold the rifle in both hands, as if to shoot, or for the "Port arms" position. For most people, the left hand will be on the fore-end, and the right hand on the butt. So if you lay it down on a workbench for dismantling, the natural tendency will be to remove the bolt with the right hand and then lay it down with the muzzle at the left. So it is natural to arrange thing so that band screws, for instance, are inserted from the left. Checking out numbering is also easier if inspection marks and/or numbers on the bands are on the left.

Like I say, NOT a rule, just more common than the other way around. Maybe it's getting late and I've slipped a cog, so please chip in anyone who can be bothered to check their own rifles!

Patrick