I'm thinking, out of all the different ways of levelling a scope they appear to be based on two assumptions;
That the reticle is absolutely square with the erector mechanism's travel. Or,
That the scope body is absolutely square with the erector mechanism's travel.
Shooters either use the verticle/horizontal reticle lines to align their scope, or they use the square edges of the scope's body (the top of the elevation turret or the flat bottom of the centre section).
So we align one of these so it is square to gravity, while coincidentally make sure the bore/scope axis is also square to gravity.
What we could (should) be doing is is aligning the scope's erector mechanism with gravity regardless of where the bore is (as long as this is how we shoot). Bearing also in mind that some reticles come canted from the factory, and this is so minimal that we don't realise. The obvious one's we return under warranty but I'll bet there are a lot out there causing problems with long range shooting and shooters don't realise why. The other assumption that the top turret or the bottom of the scope is exactly square with the erector mechanism is also based on hope and promise.
The next point is that our regular shooting position might be naturally canting the rifle. If you slowly take hold of the rifle and go into your normal cheek weld there's pressure from the cheek on the top of the butt, which cants the gun away from you. A bubble helps bring it back but I must admit it feels more natural for me to shoot a slightly canted rifle.
I'm thinking you could even go into your normal hold on the rifle, and then level the scope using one of the two ways mentioned in the thread, then check the inherent assumptions are correct (that the erector mechanism is square to gravity) by dialling up and down and watching the aiming point moving up and down a distant plumb line.
That way you can have a perfectly vertical or even a slightly canted gun but still have the erector mechanism square with gravity.
(some old bolt guns have iron sights engineered to be off to one side, so you are not mandated to have the gun/scope perfectly vertical)
Does this make sense, thoughts welcome?
That the reticle is absolutely square with the erector mechanism's travel. Or,
That the scope body is absolutely square with the erector mechanism's travel.
Shooters either use the verticle/horizontal reticle lines to align their scope, or they use the square edges of the scope's body (the top of the elevation turret or the flat bottom of the centre section).
So we align one of these so it is square to gravity, while coincidentally make sure the bore/scope axis is also square to gravity.
What we could (should) be doing is is aligning the scope's erector mechanism with gravity regardless of where the bore is (as long as this is how we shoot). Bearing also in mind that some reticles come canted from the factory, and this is so minimal that we don't realise. The obvious one's we return under warranty but I'll bet there are a lot out there causing problems with long range shooting and shooters don't realise why. The other assumption that the top turret or the bottom of the scope is exactly square with the erector mechanism is also based on hope and promise.
The next point is that our regular shooting position might be naturally canting the rifle. If you slowly take hold of the rifle and go into your normal cheek weld there's pressure from the cheek on the top of the butt, which cants the gun away from you. A bubble helps bring it back but I must admit it feels more natural for me to shoot a slightly canted rifle.
I'm thinking you could even go into your normal hold on the rifle, and then level the scope using one of the two ways mentioned in the thread, then check the inherent assumptions are correct (that the erector mechanism is square to gravity) by dialling up and down and watching the aiming point moving up and down a distant plumb line.
That way you can have a perfectly vertical or even a slightly canted gun but still have the erector mechanism square with gravity.
(some old bolt guns have iron sights engineered to be off to one side, so you are not mandated to have the gun/scope perfectly vertical)
Does this make sense, thoughts welcome?