PV,
You don't need to worry about levelling that vice.
When we level scopes we are concerned about the relationship between the scope, the barrel and the ground (gravity) only. The rest of the gun and how it is supported at the time is irrelevant to this relationship. We do however need to keep it still while levelling and a vise is a pretty good way of doing this. So, your rest and the table it sits on does not have to be level, but the Pickatinny rail does.
Looking at the relationship between barrel and scope;
[ATTACH=CONFIG]16554[/ATTACH]
A is what most shooters want.
B is what we are trying to avoid.
C is B but canted to an angle where it can work. As long as you cant the gun exactly the same angle each time and you don't have a canted rail (e.g. 20MOA) then this will work fine. Some shooters have a slight angle when they lean into the gun each time and you can build this into your levelling.
C and D are actually the same scope/barrel relationship, to show that sometimes we deliberately offset the scope. Some bench rest guns and old bolt guns have the scope deliberately offset to the side. D will also work with a forward sloping rail, so is as good as A.
E is A, but the shooter is canting the rifle - bad shooting technique, especially for long range shooting.
So, A, C and D will work but most shooters prefer A.
For A, I level the Picatinny then use a plumb line forward of the gun for the reticle. Some scope mounts come with their own bubble level however they tend to be expensive.
Here is a handy device I discovered for levelling the rail.
[ATTACH=CONFIG]16551[/ATTACH]
I just use the bubble, not the horizontal lines on the plastic ears, they are not as precise as a plumb line downrange.
Once this is done it's off to the range for a Tall Target test, to make sure the reticle has been installed square to the turret mechanisms.
You don't need to worry about levelling that vice.
When we level scopes we are concerned about the relationship between the scope, the barrel and the ground (gravity) only. The rest of the gun and how it is supported at the time is irrelevant to this relationship. We do however need to keep it still while levelling and a vise is a pretty good way of doing this. So, your rest and the table it sits on does not have to be level, but the Pickatinny rail does.
Looking at the relationship between barrel and scope;
[ATTACH=CONFIG]16554[/ATTACH]
A is what most shooters want.
B is what we are trying to avoid.
C is B but canted to an angle where it can work. As long as you cant the gun exactly the same angle each time and you don't have a canted rail (e.g. 20MOA) then this will work fine. Some shooters have a slight angle when they lean into the gun each time and you can build this into your levelling.
C and D are actually the same scope/barrel relationship, to show that sometimes we deliberately offset the scope. Some bench rest guns and old bolt guns have the scope deliberately offset to the side. D will also work with a forward sloping rail, so is as good as A.
E is A, but the shooter is canting the rifle - bad shooting technique, especially for long range shooting.
So, A, C and D will work but most shooters prefer A.
For A, I level the Picatinny then use a plumb line forward of the gun for the reticle. Some scope mounts come with their own bubble level however they tend to be expensive.
Here is a handy device I discovered for levelling the rail.
[ATTACH=CONFIG]16551[/ATTACH]
I just use the bubble, not the horizontal lines on the plastic ears, they are not as precise as a plumb line downrange.
Once this is done it's off to the range for a Tall Target test, to make sure the reticle has been installed square to the turret mechanisms.