Leveling your scope

[dmgreene]

Broz the farthest place I have to shoot right now 860 yards and I have never had to readjust a scope for vertical tracking using this method out to this distance. If you are missing left or right then I would be looking for some unnoticed wind currents or some kind of bad shooting habit (maybe even the mysterious spin drift).

Broz you are right about marking the scope, I forgot to mention that. I cut two pieces of electrical tape to a sharp point to create a couple of pointers and I stick one on the scope ring and one the scope tube. I guess a pencil mark would have been a lot easier but then again I am always trying to over complicate things.

MontanaRifleman I agree that the method that you described is a good way line everything up if the levels are accurate and nothing gets bumped, but the method that I described will prove that the scopes vertical travel is correct without a doubt. I also like to shoot a group around 7 moa and one around 15 moa to make sure everything tracking correctly. Like I mentioned before I can only shoot out to 860 yards right now and 20 moa will get me there, that's the reason I use 20 moa when checking my scopes. If you would like go to the limit of your scope's elevation you can see what effect it has on your tracking. Some scopes will do some crazy things once they get near the end of their travel.

David

 

[woods]

Wouldn't it be possible to set up or identify a vertical line at the house or at the range, set your rifle in a vise with the anti-cant device level, aim at the top of the vertical and then run the elevation and see if it stays on the vertical?

I think I am going to set up a weight on a rope about 50 yards out the back door and give it a try. If the scope tracks right down the rope and the anti-cant is set level then there can be no question.

BTW, it can be awfully hard to tighten those anti-cants down with the bubble exactly right.

 

[dmgreene]

Woods if you have way to keep the rifle in exactly in the same spot it will work. With a good vise you can do the same thing. If the rifle will return to the exact point of impact after cranking on the turrets few rounds then it will be steady enough to check the tracking.

David

 

[Magnumdude]

I don't see, short of shooting your rifle, how you can be certain the scope isn't canted a small amount. If the scope mount holes aren't drilled and tapped precisely centered with the center of the bore when the mounts are level you have a problem. It could be small it could be large. Then, ideally, the center of the bore, the mount holes, and the center of the scope should be in line, and plumb when you're ready to shoot.

I've never been able to determine how to discern all that in my shop.

I don't take this subject lightly, but I don't have enough experience to know what's good enough, nor how badly it will affect you if you only level your scope reticle without insuring it's lined up with the centerline of the bore when the whole rig is plumb.

 

[davewilson]

i'm gonna throw a monkey in the wrench here. i shoot a group at 100 yds, draw a perfectly verticle line, go up about 25 MOA. shoot another group. but i like to see the bullets hit about 1/2" to the left of verticle. this counteracts for the spin drift.

 

[woods]

Here is someone who has done some work on this

Practical Riflery Forums... techniques and equipment of the practical rifleman... :: View topic - Canted scope or canted rifle?

and some discussion right here on this site

http://www.longrangehunting.com/forums/f5/reticle-perpendicularity-darrell-holland-29352/

 

[msalm]

Now in most of the methods mentioned here, that I read anyway, it seems that everyone is assuming the scope reticle itself is mounted properly in the scope so they are in-line with the adjustments. Has anyone ever determined that their crosshairs were canted in relation to the adjustment movement??? I have a Mark 4 that seems to have this affliction. I spent a great deal of time leveling that bastard and from my 600 yard zero I can crank down to 100 yards and be shooting 4" to the left. I had a talk with a gentleman from Premier Reticles about this and he thought that was a common problem as the reticle in the Mark 4 is fitted in a keyway. Well the slot, or protrusion, on the reticle to fit that keyway has a little slop in it, and it was very common for the assembler to lock the reticle in the tube with it canted (the retainer twisted the reticle to one side of the keyway).

So now I was thinking of getting my rifle locked down in a padded vise where the scope/rifle was perpendicular and walking the elevation up a plumb line at a distance and correcting the 'cant' of the scope by trial and error...

Any thoughts on this?

 

[Mikecr]

ALL that matters in a field adjusted scope, is ADJUSTMENT plumb.
Doesn't matter how the reticle was set during manufacturing, as many use a simple dot reticle.
Doesn't matter if the bore line is different, or the gun is canted, as many competitors setup and shoot just this way.

Now you need a field reference. A ScopeLevel. So that you're shooting the same with each shot.

I must be very lucky because 4 different Mk4s I've shot the box with(including one from Premier) have tested perfect in tracking and MOA. After this testing, with the rings tight, I mount a ScopeLevel to match a temporary gun level.
From this point(doing it the same with all guns) I can move any scope from one gun to another and set it plumb on the bench everytime. Don't even need to look through it.

 

[MontanaRifleman]

ALL that matters in a field adjusted scope, is ADJUSTMENT plumb.
Doesn't matter how the reticle was set during manufacturing, as many use a simple dot reticle.
Doesn't matter if the bore line is different, or the gun is canted, as many competitors setup and shoot just this way.

Now you need a field reference. A ScopeLevel. So that you're shooting the same with each shot.

I must be very lucky because 4 different Mk4s I've shot the box with(including one from Premier) have tested perfect in tracking and MOA. After this testing, with the rings tight, I mount a ScopeLevel to match a temporary gun level.
From this point(doing it the same with all guns) I can move any scope from one gun to another and set it plumb on the bench everytime. Don't even need to look through it.

Are you really saying that it doesn't matter where the scope is aligned in relation to the bore, or am I misunderstanding you? If you're saying it doesn't matter where the scope is lined up in relation to the bore, then what if we mounted the scope to the side of the receiver/bore? What do you think would happen then?

Here's another explanation from ScopeLevel...

Scoplevel Anti Cant Leveling Device

Why do we need a level?

Because gravity pulls the bullet straight down, the bullet's path must stay directly above the line of sight.
For example, if a shooter were to make a 1000 yard shot with a 308 Win. 168 gr. Match bullet at 2600 FPS, the bullet would rise over 13 1/2 feet above the line of sight, or point of aim. Just a 6° cant, or one minute on a clock, will cause a miss of over 36 inches at that range.
Any amount of cant has a negative effect because the trajectory of the bullet will miss the vertical alignment above the line of sight.
So, the shooter today needs a level for the same reason as the old-time open sight rifle shooters needed them...FOR ACCURACY.

"...the bullet's path must stay directly above the line of sight."

That is another way of saying the scope must be "plumb" (directley above) with the bore (bullet's path)

 

[Jon A]

Any thoughts on this?

Yes. Send it back and ask for them to fix it. If they won't, get rid of it.

I agree with Mike that the only thing that matters is the adjustments being plumb...if you're the type that walks around leaning over, or don't seem to care if your head is cocked sideways or not or who hang pictures on the wall completely crooked and don't notice.

Unfortunately I'm not like that. Aiming at things with the reticle not "square with the world" is not something I care to train myself to allow, regardless of what a bubble level might say. A level can surely add some certainty to the equation, but any time the "correct" sight picture is the "wrong" sight picture, you're setting yourself up to get it "right" er, "wrong" sooner or later.

Levels are great, and can be of much help when "the world" isn't providing good visual references, but they do not fix crookedly built scopes.

When take your car in for an alignment and the guy tells you to drive your car with the wheel turned to the left in order for your car to go straight, would you pay for that alignment?

 

[jwp475]

Whether or not the rifle is level doesn't matter. The reticule however must be level. I think the fact that David Tubbs "cants" his rifle is proof enough of this fact. David has the reticule level to the horizon, but not the rifle.
Leveling the turrets does not mean that the reticule is perfectly level. A level at say 100 yards is the best way to assure a vertical reticule IMHO.

 

[Mikecr]

I shoot a T2K with 7degs of cant(like David), and it is very comfortable this way.
The article above refers to LINE OF SIGHT, and yes, you must shoot through a CONSISTENT line of sight. That is why you must use a level in the field. It should be part of your routine to verify level just prior to touching off the shot, so your level system must be viewed from shooting position(without loosing sight picture).
For this, I use only 'ScopeLevel's.

A scope could be mounted 10 feet from the bore(in any direction), and as long as your adjustments are plumb, and your gun is level as sighted, things will work just fine. You do not even need a reticle.. You can shoot with a simple dot like many others who do.

I could pull one of my scopes, with the ScopeLevel still on it and undisturbed. Install an offset base, let's say 6" left, mount the scope, re-zero.
That's it.
Plumb was already set in the past, and so shots will still track plumb as I adust through the range. This, provided I mind the gun's sighted level prior to each shot.

 

[Rimfire]

I got the Wheeler Level Level Level. I really just wanted their magnetic level for the raceway. I set a scope up using the instructions provided. Level raceways and lay the other level across the turret (cap removed) and rotate scope until both levels are reading level with each other.

I then put my 4' level out at 50 yards to see how close my cross hairs were level with the action raceways. With the raceways level a look through the scope showed **** near an inch canted at 50 yards. That's terrible. I re-checked the level on the turret it was reading dead level.

The Wheeler scope level may be ok for the home tinkerer who will only be shooting 100 yards in the woods and not using the turrets for elevation changes, but for long range use it's a piece of crap.

Question?

Doesn't the scope track off the turret? so isn't it more important to have a perfectly verticle turrett? I have seen many scopes with slightly and even seriously canted reticles. If you were to level these scopes off the Ret. you would be tracking somewere in left field. Do you check that inch canted result at 50 for canted reticle / turret alignment?

 

[MontanaRifleman]

JWP, do you have a ref for David Tubb's shooting canted. It's not that I dont believe you, but I would just like to read it to get it in context with no misunderstanding.

Mike, I still dont think I understand you, if you agiln your scope to the sdie of your bore (bullet path) you are going to induce downrange error. Also, it matters little if you are using crosshairs or dots. The dots are alinged along verticle and horizontal planes and are adjusted vertically(elevation) and horizontally(windage).

OK guys, we live in a world with certain mathematical and geometric principles as we as physical laws that include force, mass, gravity, friction, etc. And what I think I have been reading from some defies those principles and laws. and being the self appointed policeman, I am here to bust you and hand out citations

Let's make an exagerated example to illustrate.

Lets take a scoped rifle, with scope and reticle aligned vertically with the rifles bore. The center of scope rests 1.5" above the center of bore. The bullet has a BC of .3, MV of 3000 fps and zero'd in at 25 yds, at sea level. The definition of zero is the point were the bullet path meets the sight path of the scope (crosshair or dot). We will all agree that the sight path is a straightline and the bullet path is an arc'd line (which can defined by a plain) If we "aim" the scope straight ahead at the horizon, we must aim the bore in the same forward direction but slightly upward above the horizon to achieve the zero point. We also agree that the bullet will crest and begin to dip below the horizon at some point and in a no wind situation will intersect again with the scopes sight path, which in this case is exactly 250 yds down range.

OK then... now let's cant the rifle completely over on its side, 90* in a no gravity situation. If we aim and fire at our target, 25 yds away, what hapens? Correct, we hit the bulyseye or very close. If we aim and fire at our second zero, 250 yds away, what happens? The bullet impacts 13 1/2 inches to the side of the POA (second zero point). If we add gravity the bullet still impacts 13 1/2 inches o the side of POA but it also drops, approx 8-9 inches.

OK... Let's only cant the rifle 45*. The results are similar but the bullet doesn't drift quite as far to the side (approx 10 inches) nor drop as much. Actually it does drop as much, but since it is point "up" and not "straight ahaed", the drop doesn't *appear* to be as much. The farther we cant our rifle back to verticle the closer our bullet gets to POA. This not my opinon or theory. This is mathematic and geometric, physical fact.

If you always cant your rifle to the same tilt and shoot at the same zero point and distance you will always hit your POA if you zero'd in that configuration. if you shoot at different distances with a canted rifle and scope your buleit WILL drift. That is a mathematical fact.

If your reticle is not plumbed to gravity (what else would it be plmbed to?) And you dial in elevation correction, your correction will cause your POI to shift, if you use the same POA. That is not an opinion, that's a cold hard fact.

If any of you can prove otherwise on the range, I sure would be interested, because all the geometry, trigonomitry and physics books will have to be rewritten. So please do experiment. Take your rifle and cant it 45* and shoot at a target 250 or 300 yds away, and cant it again at 30*, 10* and verticle and see what happens.