what scope leveling system?

[bnewt3]

I use the wedges also but did I read somewhere that not all turret bottoms are machined the same in reference to the reticle i.e. horizontal and perpendicular? So some caution was urged about using wedges. I can't recall the exact article or wording. Anyone else heard of that?

The issue referenced is that the reticle could be canted inside the erector, or the reticle and erector might not be perfectly true to the housing. In either case, if you level the reticle, then when you dial elevation, you are also dialing a bit of windage and if you dial windage, you are dialing elevation as well. And if you level the housing, your reticle is canted and/or elevation becomes windage and windage becomes elevation.

Im not aware of any scope manufacturer that makes a housing that isnt, or shouldnt be, flat and square on the bottom.

It the same issue that CAN exist with EVERY scope mounting method.

This is why when shooting any significant distance(like maybe beyond MPBR), you need to do a tall target test after zeroing. This will reveal those issues inside the optic.

 

[MT_Wyatt]

I’ve had good luck using that Defensive Edge kit UM sells. Works quite well. Have tried a wedge, action/turret levels from wheeler, etc and just prefer the DE system. Ring cap levels continue to be a pain.

 

[Firth]

I have one of these:

Parabola LLC

parabola-llc.com

I think it works pretty well. The biggest trick is aligning the tool with the reticle. After that you line the tool up with the bore.

 

[Ryan_1129]

Appreciate the replies

 

[Stud Duck]

I have one of these:

Parabola LLC

parabola-llc.com

I think it works pretty well. The biggest trick is aligning the tool with the reticle. After that you line the tool up with the bore.

I've used about every system known to man and the Parabola is what I've used for the decade or so; works well.

 

[Jordan Smith]

The Parabola Reticle Tru is great when the scope/rifle lack a flat surface from which to indicate that the two are parallel.

Instead of wedges, I use segments of a multi-piece cleaning rod held to the top of the receiver/pic rail and the bottom of the erector housing using elastic bands. Ensure that the rods are centered and parallel, and then rotate the scope until the "indicator" rods are equidistant on both sides of the rifle. Now the erector housing is parallel with the top of the receiver/pic rail. Align the reticle with a plumb line, rotate the scope level to center the bubble, and tighten the level. Done. You can validate that the erector and reticle are parallel using an optical grid like the Bushnell magnetic boresighter. Align the grid with the reticle, dial the turrets and make sure there is no reticle drift. No need for a live-fire TTT to confirm that.

 

[wind gypsy]

We should really make a sticky for this topic. It comes up every few months and the amount of silly shit people suggest or waste their time doing is surprising in every thread.

 

[ruger35]

I use the SAC level either in the vise or my tripod. Level the scope and attach bubble level, then it goes on whatever gun I’m shooting from there.

 

[Castle Rock]

We should really make a sticky for this topic. It comes up every few months and the amount of silly shit people suggest or waste their time doing is surprising in every thread.

Yep, it’s unbelievable the lengths people go to to do the simplest things.
Hold the rifle in a rest or bipod so it doesn’t move, pull your head back a bit and make sure the vertical cross hair lines up with the center of the cocking piece.

 

[Speaks]

Dosnt really matter if its perfectly level to your action, matters that its level to gravity when you shoot. Level to the bubble on your rail which should be very close to level with your action. Then shoot with your rail bubble leveled.

 

[Wrench]

Around the 7:30 mark gets to the meat and potatoes of a good way to see the effects of your ring torque.

 

[Jordan Smith]

Dosnt really matter if its perfectly level to your action, matters that its level to gravity when you shoot. Level to the bubble on your rail which should be very close to level with your action. Then shoot with your rail bubble leveled.

It does make a difference, but that difference may or may not be significant for your application.

 

[Coopsdaddy]

Used this and plumb bob on my last few.

 

[Speaks]

It does make a difference, but that difference may or may not be significant for your application.

Fair enough.

Why does it make a difference if its perfectly level to the action vs perfectly level to gravity? I get that generally speaking you want to shoot with the action level so they ideally would be one and the same. But to the degree the scope is held level to gravity and the action is off a degree or two what difference would it actually make?

And I am not saying you are incorrect, genuine question.

 

[Jordan Smith]

Fair enough.

Why does it make a difference if its perfectly level to the action vs perfectly level to gravity? I get that generally speaking you want to shoot with the action level so they ideally would be one and the same. But to the degree the scope is held level to gravity and the action is off a degree or two what difference would it actually make?

And I am not saying you are incorrect, genuine question.

Yes, exactly. Gravity operates in the vertical plane, so the vertical relationship between the bullet's trajectory and the scope's optical axis will deterministically vary with distance. Ideally, you want both the scope axis and the rifle bore axis to be aligned in that vertical plane. The reason for this is that the scope axis and the bore axis/bullet trajectory are not co-located - they intersect at your zero distance - and you want there to only ever be a vertical offset between the two, if possible. If there is a horizontal offset at the muzzle, but none at your zero distance, then that offset will continue increasing linearly as distance increases beyond the zero distance. If we assume that the scope axis is 2" above the bore axis, a 5 deg cant translates to 0.2" horizontal offset at the muzzle. If you're zeroed at 100 yards, then the bullet is moving horizontally, relative to the scope axis, by 0.2" per 100 yards. You're inducing an extra ~0.2 MOA of windage into your bullet's trajectory unintentionally, which acts as a confounding variable when solving for a windage hold. Now, does a ~2" offset at 1000 yards matter to a hunter? No. Does it matter to a 1000-yard BR shooter? Yes, and they would need to account for it.

Given how simple it is to square a scope to a rifle, why not eliminate that variable, whether it is significant to you or not.

 

[bnewt3]

AFAIK most, maybe all, ballistic solvers don't have a way to input horizontal offset from bore, only vertical offset(scope height). In other words solvers assume the optic is directly over the bore.

 

[Speaks]

Yes, exactly. Gravity operates in the vertical plane, so the vertical relationship between the bullet's trajectory and the scope's optical axis will deterministically vary with distance. Ideally, you want both the scope axis and the rifle bore axis to be aligned in that vertical plane. The reason for this is that the scope axis and the bore axis/bullet trajectory are not co-located - they intersect at your zero distance - and you want there to only ever be a vertical offset between the two, if possible. If there is a horizontal offset at the muzzle, but none at your zero distance, then that offset will continue increasing linearly as distance increases beyond the zero distance. If we assume that the scope axis is 2" above the bore axis, a 5 deg cant translates to 0.2" horizontal offset at the muzzle. If you're zeroed at 100 yards, then the bullet is moving horizontally, relative to the scope axis, by 0.2" per 100 yards. You're inducing an extra ~0.2 MOA of windage into your bullet's trajectory unintentionally, which acts as a confounding variable when solving for a windage hold. Now, does a ~2" offset at 1000 yards matter to a hunter? No. Does it matter to a 1000-yard BR shooter? Yes, and they would need to account for it.

Given how simple it is to square a scope to a rifle, why not eliminate that variable, whether it is significant to you or not.

Got it, that makes sense.

I might have to go look. I generally mount the UM tikka level and compare to the level on the flat top, then level the scope to the bubble, so in theory should be good but not I feel like I should double check without the middle step and compounding errors etc.

 

[wind gypsy]

Obligatory post of tables that end up being posted every time this discussion comes up.

 

[Jordan Smith]

AFAIK most, maybe all, ballistic solvers don't have a way to input horizontal offset from bore, only vertical offset(scope height). In other words solvers assume the optic is directly over the bore.

Some, like Ballistic AE, do.