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Thread: Scope Cant/Tilt

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    Member Smokey's Avatar
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    Default Scope Cant/Tilt

    I was curious if you mount a scope on a rifle and get it with a slight cant ( I imagine a very high percentage of scopes are just eyeball mtd ) would it not show up as you increase the yardage like:
    at 100 say 1in high left
    at 200 maybe dead on or slightly low right
    at 300 even more low right etc etc...
    I would think the further distance would show a constant bullet "walk" ?
    Any input fella's ? I do not shoot much over 200 on a regular basis to be sure but seems logical to me...
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Moderator LuJon's Avatar
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    I read an article on this a little while ago that went into a great deal of detail on it, complete with charts and graphs. I may still have it laying around somewhere so will have to see about digging it out when time allows. Here is one on the web that is not nearly as in depth. In the end your assumption regarding distance increasing the degree of deviation is accurate.

    http://www.chuckhawks.com/canting.htm

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    Member sayak's Avatar
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    Quote Originally Posted by Smokey View Post
    I was curious if you mount a scope on a rifle and get it with a slight cant ( I imagine a very high percentage of scopes are just eyeball mtd ) would it not show up as you increase the yardage like:
    at 100 say 1in high left
    at 200 maybe dead on or slightly low right
    at 300 even more low right etc etc...
    I would think the further distance would show a constant bullet "walk" ?
    Any input fella's ? I do not shoot much over 200 on a regular basis to be sure but seems logical to me...
    Well, that is an unsettling thought, seeing that I have "eyeballed" the level when mounting all my scopes. I know that there are levels that can be used to make sure scopes are mounted level, but...
    Hypothetically speaking, however, if the rifleman doesn't hold the rifle exactly level, then wouldn't the same walking you speak of also be in play?

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    sayak, like you I have been using the eyeball measure & meter tool all of my life until.........I dared buy Midways level leveler for scopes. I liked the subtle adjustments and/or surprising adjustments I've had to make on my scoped rifles. So if I was or thought pretty precise in my accuracies in the past now I should be? We'll see this year. ha

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    Member Smokey's Avatar
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    Quote Originally Posted by sayak View Post
    Well, that is an unsettling thought, seeing that I have "eyeballed" the level when mounting all my scopes. I know that there are levels that can be used to make sure scopes are mounted level, but...
    Hypothetically speaking, however, if the rifleman doesn't hold the rifle exactly level, then wouldn't the same walking you speak of also be in play?
    Good question, but I think it would not matter how the shooter held the gun as the bullet does not recognize that, you could lay a gun on its side and shoot it and the bullet drop would still be consistent. When using a scope you are trying to get the scope to do what the bullet does naturally not the other way around... Hope that makes sense?
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    I recently leveled up the scope on my Ruger No. 1 and saw no measureable impact at 100 yds. For a No. 1 it was easy - I used the flat side of the receiver and the top scope cover.
    Living the urban lifestyle so I can pay my way and for my family's needs, and support my country. And you?
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    Quote Originally Posted by grizz106 View Post
    sayak, like you I have been using the eyeball measure & meter tool all of my life until.........I dared buy Midways level leveler for scopes. I liked the subtle adjustments and/or surprising adjustments I've had to make on my scoped rifles. So if I was or thought pretty precise in my accuracies in the past now I should be? We'll see this year. ha
    Hey Grizz106, I am with you boyz - the old eyeball level - yup that looks right!
    So now I am thinking - which usually costs me money - is that unit you bought the "Site-Lite SL -100 Mag model by chance"?
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Moderator LuJon's Avatar
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    Canting the rifle definitely will affect accuracy at a distance! ....dang I need to find that article!

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    Moderator LuJon's Avatar
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    Here are some better examples with diagrams that help to explain it.

    http://www.riflescopelevel.com/cant_errors.html

    http://www.accurateshooter.com/optic...int-of-impact/

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    That is why the better iron target sights include level glasses. And iron sights are mounted closer to the barrel so tilt is less significant than scopes mounted higher above the bore.

    Quote Originally Posted by LuJon View Post
    Canting the rifle definitely will affect accuracy at a distance! ....dang I need to find that article!
    Living the urban lifestyle so I can pay my way and for my family's needs, and support my country. And you?
    ".. ask not what your country can do for you, ask what you can do for your country" JFK

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    Quote Originally Posted by Smokey View Post
    Good question, but I think it would not matter how the shooter held the gun as the bullet does not recognize that, you could lay a gun on its side and shoot it and the bullet drop would still be consistent. When using a scope you are trying to get the scope to do what the bullet does naturally not the other way around... Hope that makes sense?
    You can't lay a gun on it's side and shoot using the scope and get the same POI. On it's side your elevation reticle is now your windage and vice versa. The settings would be totally off. I've always been told it's highly important to hold your rifle as nearly plumb as possible for that very reason.

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    Quote Originally Posted by evandailey View Post
    You can't lay a gun on it's side and shoot using the scope and get the same POI. On it's side your elevation reticle is now your windage and vice versa. The settings would be totally off. I've always been told it's highly important to hold your rifle as nearly plumb as possible for that very reason.
    You are right on evandaily! I was not clear enuff - what I tried to say was a bullet will fly out of a bbl and drop repeatedly in the same flight path no matter what position the gun is in -statement has nothing to do with a scope or sites - bullet only knows its leaving a bbl and will start to drop.
    With the addition of a scope the bullets are not really moving, the scope is...
    When asked what state I live in I say "The State of Confusion", better known as IL....

  13. #13

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    If the scope or rifle is canted it will affect POI down range. The farther down range, the more the effect and the higher the scope is mounted the more the effect. If you mount the scope canted right and hold the scope grasshairs level. the bullet will impact low and to the left the farther down range you go. If you mount the scope level (or plumb) to your rifle's action and cant the rifle right, your POI will be to the right and low. Being a long range shooter, this is important to me so I take pains to mount the scope plumb to the rifle's action and I also mount an anti-cant bubble to my scope. The method I use to mount the scope is to hang a string with plumb bob from the wall of my shed, then set my rifle up on bi-pod and rear bag on a fold out table about 10 yards away. I torque the ring bottoms to the rail mount and place the scope in the bottoms. Then I place the tops and screw them down enough to leave some room for adjustment of the scopes cant. Then I remove the bolt and eyeball down the bore and split the bore with the hanging string and plum bob. The I adjust the cant of the scope so the windage reticle is aligned with the string. Then torque the screws and recheck the alignment. Then I level the anti-cant bubble level and torque it down. It seems to work for me. When I started checking my level on the bench at the range, it was a real eye opener. I found myself inducing a lot more cant than I would have guessed without using the level.

    For shooting out to 300 yds or so, eyeballing served me well... close enough to get the job done.

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    woooo... I like the plumb bob idea. of course that would require me to find some section of my garage floor that was level to put a fold out table on.
    “You’ve gotten soft. You’re like one of those police dogs who’s released in to the wild and gets eaten by a deer or something.” Bill McNeal of News Radio

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    Member Smokey's Avatar
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    Thx Montana for that input - I think its a very usable method for almost everyone for sure and simple.
    I know there are many threads on here talking about "long range shooting" and I thought this might stimulate some chatter of interest for those wanting to learn how to become proficient at say a 400 yard ram...
    For the vast majority you are right - 95 % of our kills are 200 yards or less I would guess and the avg deviation at that range is nill.
    I have hung a plumb years ago in my basement and I like that as a gauge. I have never used a level though and in one of Lujons attachments there is a pretty nifty one built into a scope ring that I kinda like - might be worth a purchase! Don't need one on every gun but wouldn't mind one set up to pokem way out there with confidence!
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Quote Originally Posted by MontanaRifleman View Post
    If the scope or rifle is canted it will affect POI down range. The farther down range, the more the effect and the higher the scope is mounted the more the effect. If you mount the scope canted right and hold the scope grasshairs level. the bullet will impact low and to the left the farther down range you go. If you mount the scope level (or plumb) to your rifle's action and cant the rifle right, your POI will be to the right and low. Being a long range shooter, this is important to me so I take pains to mount the scope plumb to the rifle's action and I also mount an anti-cant bubble to my scope. The method I use to mount the scope is to hang a string with plumb bob from the wall of my shed, then set my rifle up on bi-pod and rear bag on a fold out table about 10 yards away. I torque the ring bottoms to the rail mount and place the scope in the bottoms. Then I place the tops and screw them down enough to leave some room for adjustment of the scopes cant. Then I remove the bolt and eyeball down the bore and split the bore with the hanging string and plum bob. The I adjust the cant of the scope so the windage reticle is aligned with the string. Then torque the screws and recheck the alignment. Then I level the anti-cant bubble level and torque it down. It seems to work for me. When I started checking my level on the bench at the range, it was a real eye opener. I found myself inducing a lot more cant than I would have guessed without using the level.

    For shooting out to 300 yds or so, eyeballing served me well... close enough to get the job done.
    Maybe I missed something but how did you level your gun on the bipod and rear bag? I like the plumb bob idea better than the Level/level I use now.

  17. #17

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    Quote Originally Posted by markopolo50 View Post
    Maybe I missed something but how did you level your gun on the bipod and rear bag? I like the plumb bob idea better than the Level/level I use now.
    I assume by level, you men side to side level or plumb in the vertical. The bi-pod is what I had. My field rifles wear bi-pods. A good rifle vise with leveling screws would be better. With a bi-pod it's more important to have your table level so you can easily plumb your rifle action. The rear bag helps with elevation and also helps to stabilize the rifle.

    Another thing, the sturdier the table the better. The next time I do this I'll do it from my home made 3 leg shooting bench which is pretty solid for a portable table.

  18. #18

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    Quote Originally Posted by Smokey View Post
    Thx Montana for that input - I think its a very usable method for almost everyone for sure and simple.
    I know there are many threads on here talking about "long range shooting" and I thought this might stimulate some chatter of interest for those wanting to learn how to become proficient at say a 400 yard ram...
    For the vast majority you are right - 95 % of our kills are 200 yards or less I would guess and the avg deviation at that range is nill.
    I have hung a plumb years ago in my basement and I like that as a gauge. I have never used a level though and in one of Lujons attachments there is a pretty nifty one built into a scope ring that I kinda like - might be worth a purchase! Don't need one on every gun but wouldn't mind one set up to pokem way out there with confidence!
    Mucho welcome Smokey... I have two scope levels. One is actually in the top ring of my Sendero 300 RUM. It's a Nightforce product and only fits NF rings which are spendy. I got it from Defensive EDGE.

    http://www.defensiveedge.net/product...MOUNT%2013.htm

    The other I got from Sinclair, MGW ACD... I just got it and it's going on my Sendeor so i haven't used it yet. It's not as rugged as the NF level, but a whole lot less costly. Time will tell on how well it does. The NF vesions is definitely top line. I don't care for the high profile ones and the ones that mount to your rail are only as accurate as your rail is level and they make a great snag - not what you want for a hunting rifle.

  19. #19

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    I've always wondered about those action leveling kits like the Wheeler Level,Level,Level. What exactly are they referencing off of on the action? the bolt rails or what? I mean for the most part actions are round (except on the bottom of some which is in the stock) so what surface is getting leveled?

  20. #20

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    Quote Originally Posted by evandailey View Post
    I've always wondered about those action leveling kits like the Wheeler Level,Level,Level. What exactly are they referencing off of on the action? the bolt rails or what? I mean for the most part actions are round (except on the bottom of some which is in the stock) so what surface is getting leveled?
    I don't consider them to be very reliable.. A plum bob is referenced off gravity.

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