Anti-Cant devices that actually work....?

[Gunslinger]

How do you find true level of your rifle?

The width of the Picatinny/Weaver mount allows you to place a bubble level on it to level the gun, it's a small surface so you have to make sure the level is flat on it and laid perpendicular to the action. Once indicated level the scope is rotated in the rings to be plumb, I sight at a vertical plane on a window outside a short distance away since most windows are installed level and plumb. Now adjust the anti cant to show level with the rifle level. The plane of the two levels should now be parallel to each other and perpendicular to the vertical cross hair. To check aim at the window again and align the vertical cross hair, the anti cant bubble should be dead centre indicating level. Now anytime you shoot as long as your anti cant indicates level your gun will be level and the vertical cross hair perpendicular to it allowing proper vertical adjustment. More importantly though the line drawn from your aim point down through the vertical cross hair and through the centre of the barrel should be perfectly aligned with the trajectory/drop of the bullet. If not aligned while firing your barrel will be either left or right of the aim point, if left (right cant) you bullets will land slightly right of the target, if right (left cant) slightly left.

 

[ivo]

I use the US Optics on 2 rifles but will try a Flatline Ops on the next one. Nothing wrong with USO just want to try something different.

 

[paperslayer]

the point of an anti-cant device is just to keep the rifle in more or less the same position from shot-to-shot regardless of how your scope is mounted.

 

[dthunter]

Ultimate monkey said it right.
I have responded to this very question a number of times before! It never gets through to some people.


The rifle being level is of the smallest importance in the equation. That doesnt mean set the crosshairs at a 45 degree angle!

The proceedure I use is (basically identical to ultimate monkeys):

1.) Set A Plumb bob on your target at 100.

2.) tilt your "slightly loose scope until the vertical crosshair is as Parallel to the plumb line as possible. I like to leave a slight gap between the line and crosshair to visualise my alignment.

3.) adjust your loose and already closely positioned level to perfect level. Snug down slowly, and repeatedly double check to be sure the level hasnt been toqued to one side as its tightened.

4.) once the scope/level relationship is true and tight, then adjust your rifle and scope relationship to where you feel comfortable. EXACT alinment of the rifle and scope AGAIN is of the least
Importance. But do your best non the less. The higher the scope is mounted/ the
More the potential for alignment errors. But I have proven to myself and many others this doesnt amount to anything significant.


The most important factors are that the "scope" is consistantly level while being shot. The scopes vertical adjustment plane is what moves and therefore must me the consistant and minimized variable.

This is as simple as it gets guys, lets not flame others who dont understand it. At times I have difficulties explaining it as well.
Please feel free to add anything I may have ommitted or explained unclearly.

 

[dthunter]

Half the battle is trying to explain ourselves, let alone a complex Subject.

Hope I didnt offend anyone in particular in my last post.
Biggest thing in this long range shooting is to get a rifle setup and consistantly shooting precisely where you want it at long range. It dont really matter how you do it, as long as you can "repeat it at will".

 

[flyerhawk19]

Seen some precision shooters have their scope NOT level to their gun, so when they set up in their natural aiming position of the rifle is not level but the reticle will be. They set up a cant to conform to their body.

I don't see how a small cant in the rifle with the reticle level when you are aiming will make any difference beyond the shooters capabilities (within reason of course).

 

[rnbra-shooter]

Seen some precision shooters have their scope NOT level to their gun, so when they set up in their natural aiming position of the rifle is not level but the reticle will be. They set up a cant to conform to their body.

I don't see how a small cant in the rifle with the reticle level when you are aiming will make any difference beyond the shooters capabilities (within reason of course).

In fact, provided your *scope* is level, you can have a huge cant in the *rifle*, with essentially zero effect.

Rifle cant does not matter. Scope cant does. There's no need to align the scope to the rifle. Only the scope to the target.

 

[ultimate_monkey]

^^^^ thank fuk I'm not the only one who gets it

 

[mark k]

What do people think of the Nightforce unit that has it built into the top ring?

 

[ultimate_monkey]

Personally not a fan, they are hard to see with out breaking your cheek weld and then trying to get back into position with out moving the rifle . Ones like the flatline ops and USO that are off to the side allow them to be seen with out having to move your head aroud

 

[75-B]

Vortex makes one. Not bad if your sand bagging or got the harris bipod unfolded.

 

[pilot2001]

Delete

 

[Crashman]

Vortex makes one. Not bad if your sand bagging or got the harris bipod unfolded.

I use the same one but I mount it out in front of the scopes turrets. This way when I am behind the rifle shooting I can see the level with my left eye (I am a right hande shooter) and it actually appears as if the level is inside the scope (optical illusion). Once I am lined up and ready to shoot I close my left eye and the level disappears. Works for me.

 

[cody c]

Hey Guys,

Looking for a way to set up my scope to be level with the gun, and ensure my shots in the field are as level as possible. I was looking at some anti-cant devices, and honestly, the ones I do find (fit around scope) seem flawed, because well, how does it anchor to your gun to ensure it is level with the gun?

Thanks for all the help/advice and do our sponsors carry some?

So you started a thread saying that you dont think anti cant (scope bubble levels) work, then you say you have no idea as how to mount them?

check out you tube. If you need help finding out how a bubble level works talk to a carpenter he should be able to give you instruction as to how it functions.

 

[PeanutGalleryShooter]

Horus' ASLI™ offers a slope indicator and cant indicator in one unit for about half the price of a similar unit (w/o bubble level) offered by Nightforce or Snipertools. For mounting, my personnal preference would be for the Badger Ordnance Gen ll ACI Picatinny Rail Mount.

 

[Kevin M.]

Not a cheap solution, but the best solution I have ever seen.

SPUHR Ideal Scope Mount.

It has a built in bubble level for controlling cant.

To level the scope on the mount, they came up with a brilliant solution. A simple mechanical 10 degree wedge that fits into a slot and interfaces with the bottom of the flat part of your scope.

No playing around with plumb bobs or levels, no guess work, just straight up results.

I have two of them, both on .50BMG rifles, and can report that they are the best mounting system I have ever used.

And the wedge that slides into the slot to level your scope...

 

[flyerhawk19]

^^^^ thank fuk I'm not the only one who gets it

You are most welcome my dear sir, would you care for a spot of milk in your tea?

 

[Haagen_Dazs]

1) the scope needs to be perfectly plumb/ level with the bore - COMPLETE HORSE SH!T, as long as your not ridiculously retarded about being able to eye something up level and plumb over a 2" span the difference that will be made in your shooting is less then the MOA the gun will actually shoot , so unless your anal retentive and shooting a true 1/4minute or less gun it doesn't matter

2) put the gun in a gun vice, hang a plumb bob , at a reasonable distance so you can fous your scope on it. line your virtical x-hairs up with the string, then install scope level, so well its level, done deal

True, the scope and bore axis need not be plumb.


BUT


The crosshairs MUST be plumb to gravity otherwise your elevation/windage adjustments will not be a true 1/4 MoA (or 0.1 Mil). In addition, the elevation adjustment will put your windage off and Vise-Versa. Hopefully that is clear as mud.


In order to ensure our cross hairs are plumb from shot to shot, we install Anti-Cant devices on our rifles. The set up is as critical as the understanding. If done improperly, your scope will not track is intended (1 click up will result in 0.9 click up and 0.1 click sideways for example).

the difference that will be made in your shooting is less then the MOA the gun will actually shoot

This set up has nothing to do with group size (precision), it's all about shot placement (accuracy).


2 types of Anti-Cant devices:
a) Rail Mounted
b) Scope Tube Mounted


How to Install a Rail Mounted anti-cant:
1) Attach bottom halves of scope rings and anti-cant to rail.
2) Place scope in rings, adjust for eye relief, and loosely screw on top halves of rings.
3) Go to range, at 50-100 yards, tie a rock to a string and hang it from a target (plumb line)
4) Set up rifle in sturdy rest and level the bubble on your anti-cant
5) Rotate scope in rings until vertical crosshair lines up with plump line
6) Tighten screws, ensuring bubble remains centered and scope remains plumb!

How to Install a Scope Tube Mounted anti-cant:
1) Attach bottom halves of scope rings to rail.
2) Place scope in rings, adjust for eye relief, and loosely screw on top halves of rings.
3) Go to range, at 50-100 yards, tie a rock to a string and hang it from a target (plumb line)
4) Set up rifle in sturdy rest and rotate scope in rings until vertical crosshair lines up with plumb line
5) Tighten screws, ensuring scope remains plumb!
6) Affix anti-cant to scope tube, tighten with bubble centered, insuring rifle does not rotate/scope remains plumb

Easy right?!

 

[ultimate_monkey]

True, the scope and bore axis need not be plumb.


BUT


The crosshairs MUST be plumb to gravity otherwise your elevation/windage adjustments will not be a true 1/4 MoA (or 0.1 Mil). In addition, the elevation adjustment will put your windage off and Vise-Versa. Hopefully that is clear as mud.

i agree, what i meant was that if your scope is 1 or 2* off plumb with your bore, its effect wont even be noticeable as long as your shooting with your xhairs plumb

 

[rnbra-shooter]

True, the scope and bore axis need not be plumb.

Absolutely agreed.

Not only that, they don't even need to be close. You could mount your scope canted 30 degrees to the right in the rings. The two biggest drawbacks would be that it would look pretty stupid, and that in many cases it would be pretty awkward to shoot the rifle well (while shooting, in order to keep the crosshairs level on the target, you'd have to can the rifle 30 degrees to the left).

BUT


The crosshairs MUST be plumb to gravity otherwise your elevation/windage adjustments will not be a true 1/4 MoA (or 0.1 Mil). In addition, the elevation adjustment will put your windage off and Vise-Versa. Hopefully that is clear as mud.

To elaborate on your statement, The crosshairs MUST be plumb to gravity when you are shooting. It doesn't matter how plumb they are/are-not as they are installed on the rifle.

Regarding adjustments will not be a true 1/4 MoA (or 0.1 Mil)., that's ends up being little to no problem. A 10-degree cant (very, very visible) will turn a 1-MOA windage adjustment on your scope into an actual sideways adjustment of 0.985 MOA - which would be utterly indistinguishable. To go to extremes, a 30-degree can would turn a 1-MOA windage adjustment into an actual sideways movement of 0.87 MOA - which in most cases would be difficult for a shooter to detect.

The problem that canting causes for long range shooting is that when you have a large amount of elevation adjustment dialled onto your sight (as you do when shooting at long range), a cant will produce significant sideways offsets due to the sight's elevation becoming cross-coupled to the windage. There is also an equivalent cross-coupling effect from windage to elevation, but since we typically have much smaller windage adjustments than elevation offsets, this is usually not noticeable.

Let's say I am shooting at 1000 yards, and in order to do this I have put 32 MOA of 'up' on my scope.

Let's say we have enough wind is blowing that I need to put 5 minutes of left windage on my scope. So I put 5 MOA 'left' on my scope's windage adjustment.

If I aim the rifle with the scope held level, I'll hit where I am aiming. So far so good.

Now let's say I cant the rifle 5 degrees to the right (which is a modest, but definitely-noticeable cant if you are firing in a uniform place such as a rifle range). The Sine of 5 degrees is 0.087, therefore we get a cross-coupling of 0.087 (the sine of 5 degrees).

That means that the 0.087 of rifle's 32-MOA elevation adjustment gets fed (cross-coupled) into the horizontal offset of where the rifle's barrel is actually aiming.

It also means that 0.087 of the rifle's 5-MOA windage adjustement gets fed (cross-coupled) into the vertical offset of where the rifle's barrel is actually aiming.

Here are the numbers:

windage effect = 0.087 * 32 = 2.8 MOA of windage offset.
elevation effect = 0.087 * 5 = 0.4 MOA of elevation offset.

Having just fired a bullseye at 1000 yards with the rifle held level, you'll now see your bullet land 2.8MOA to the right (i.e. in the direction of your cant). In most cases this will be pretty noticeable (even worse is if you don't notice it, and interpret what you see on the target as there having been a 2-3 MOA wind change that you haven't seen)

Your bullet will also strike 0.4 MOA lower than where it would have if you had fired the rifle with the sight held level, however in most cases you probably won't be able to notice this (in most cases if you are shooting a 1 MOA group at 1000y you are shooting well enough to win the match).