Rifle canting and levels

[WildRose]

Here's another way to use the same tool. This isn't even in English and it's still so simple it's stupid. Start at the 3:00 mark.

 

[brody04]

Thanks wildrose, that seems easy enough to at least get it really close.

 

[Canhunter35]

Joe,
Did you figure out why your poi was shifting?

 

[Joefrazell]

Joe,
Did you figure out why your poi was shifting?

I still have not. Ive been out hunting the last few weeks on my days off and haven't had time to yet. The gun killed a black bear a week ago though I did buy a level system and used it on another rifle already. I feel it only will get it very close but not perfect. I will let you guys know what I find when I have some free time again

 

[Canhunter35]

I have my scopes trued to the action but if you watch videos of David Tubb he holds his rifle canted where it's comfortable to him and only has the scope level...to me it makes sense. The bore of the rifle is only 1/8" to the right on a major can't, minor detail. Next rifle I set up I will try positioning the scope like he advises...can't bring myself to change a zeroed rifle lol

 

[7magcreedmoor]

This is my favorite tool for getting the scope and bore plumb with each other:

Once the rig is plumb, a level on top of the turret and/or a plumb line on the wall to line up the reticle, torque the ring screws carefully with the levels in place to avoid inadvertently rotating the scope with the wrench, then a tall target test to confirm.

 

[Joefrazell]

After leveling the scope to the bore and the level with the wheeler tool all is well. Shot out to 800 and it's good to go on two rifles. I thought some small adjustment may be needed but the targets have argued otherwise.

 

[Rhovee]

I recently went through the same thing. After mounting the scope and leveling it as best as i could, i checked the levels to each other and they were way off. If i set up a laser level in the garage and put a level in the action and top of the scope they wouldn't line up perfectly. I could be wrong here. But if the scope cross hairs are level, how would the action being off a little matter? Are main point is to make sure the scope tracks in a vertical plane. Having a anti cant level installed on the scope and leveled with the cross hairs would mean more to me for shooting.

 

[RockyMtnMT]

I recently went through the same thing. After mounting the scope and leveling it as best as i could, i checked the levels to each other and they were way off. If i set up a laser level in the garage and put a level in the action and top of the scope they wouldn't line up perfectly. I could be wrong here. But if the scope cross hairs are level, how would the action being off a little matter? Are main point is to make sure the scope tracks in a vertical plane. Having a anti cant level installed on the scope and leveled with the cross hairs would mean more to me for shooting.

If the scope is not level to the rifle it will cause left/right issues when dialed for distance.

Steve

 

[Hand Skills]

I have my scopes trued to the action but if you watch videos of David Tubb he holds his rifle canted where it's comfortable to him and only has the scope level...to me it makes sense. The bore of the rifle is only 1/8" to the right on a major can't, minor detail. Next rifle I set up I will try positioning the scope like he advises...can't bring myself to change a zeroed rifle lol

This is an interesting point. I was mentored to install scopes while holding the rifle. I.e. I hold my rifle while somebody else rotates the reticle to plumb. This works really good if you shoot primarily offhand, or primarily sitting, and often there ones own anatomy induces some cant in the rifle. This is fine for shooting to intermediate (500-600yd) distances.

Truly long range shooting is a different discipline. Once vertical corrections reach several feet, well as we all know, small factors start to show up. For those who holdover, it becomes increasingly important that the reticle is plumb (through the bore). For those dialing, it becomes increasingly important that the vertical erector is parallel with the SCOPE/BORE AXIS.

Let me repeat that; if you are dialing it does not matter if your reticle is level - it's the mechanical assembly in the scope that needs to be aligned with the imaginary plane running through the center of your scope and bore.

Let's say your reticle is perfectly level as most people say (or plumb as we carpenters say). Your rifle is shot in a perfectly 'level' condition. Reticle cant will show up.

let's assume 2deg of relative difference between the reticle and the erector assembly;

For an example, we are dialing 16moa of elevation at 800yd.

16(MOA) x 8(hundred yards)= 128" of vertical 'come up'

Tan 2deg = 0.03492

128" x .03492 = 4.47"

2 degrees translates to almost 4.5" of error in this example. So, we have PERFECTLY levelled our reticle and our rifle, but have weird lateral POI shifts showing up.

This is why the 'tall target test' is so important.

 

[Rhovee]

I haven't done a test to determine my theory. But if the bullet, chamber, action are concentric and tried to .001 of an inch. Theory would mean it wouldn't matter as much as the scope being level to the action as the scope crosshairs being level to the target. But even at that your scope may not be tracking correctly. The consent of your reticle not being level and dialing makes perfect sense. It's like a boat sailing 2 degreees of coarse.

 

[Hand Skills]

I haven't done a test to determine my theory. But if the bullet, chamber, action are concentric and tried to .001 of an inch. Theory would mean it wouldn't matter as much as the scope being level to the action as the scope crosshairs being level to the target. But even at that your scope may not be tracking correctly. The consent of your reticle not being level and dialing makes perfect sense. It's like a boat sailing 2 degreees of coarse.

Indeed - unfortunately the closest 'index' we have to the erector assembly are the scope caps. There is no way to guarantee the tracking of an erector assembly without testing it.

It's ok, it's only rocket science.

 

[Adikted]

I have my scopes trued to the action but if you watch videos of David Tubb he holds his rifle canted where it's comfortable to him and only has the scope level...to me it makes sense. The bore of the rifle is only 1/8" to the right on a major can't, minor detail. Next rifle I set up I will try positioning the scope like he advises...can't bring myself to change a zeroed rifle lol

There's a big difference between shooting a canted rifle on a known distance range and a hunting situation where the shot can be at any range.

The bullet begins falling from the bore line as soon as it leaves the muzzle.

In order to compensate for that your bore line and sight line aren't parallel.

Think of the bore line being uphill and the sight line being level.

If your bore isnt directly below the center of your sight line the bore its pointing to the left or right compared to the sight line

Your bullet will only be able to cross your sight line at a single point.

David Tubb does not care about this because he only needs it to cross at the target which is a known distance.

If your bore line is directly below your sight line your bullet is able to cross your sight line at any point in its trajectory.

 

[Rhovee]

I understand what your trying to say and agree. I just have a hard time trusting those levels. I have 4 small levels that came with some kits. If u put all of them on a concrete bench they are not all leveling the same. I think each time you level a scope, a tall target test is the sure sign if your off or not. So left one level on the action. Put a laser plum bob on the wall and made the cross hairs level with the action. Then put an anti cant level on the scope.