Rifle Scopes Trust the level or the eye?

[kentactic]

ive got a level that attaches to the picatinny rail and ive got a level on top of the scopes turret. if it matters the scope an SWFA 10X42HD.

when i level the scope with the bubbles the reticle looks way canted. and when i level it by what my eyes think is level basing it off the rail level the level on the turret says its way canted. i shoulder the rifle on both sides to make sure its not the side im on percepting it this way... with the way i see it as level its level no matter which eye. with the levels version of level both eyes say the reticle is totally canted.

is this a canted reticle in my scope or can i not trust that the turret is level to begin with? or is this a canted base situation? or are all of the above a possiblity?

-Kenny

 

[Graham]

Re: Trust the level or the eye?

..and that's the problem with bubble levels, and one reason why I don't use one despite what the internet says about whether or not I need one.

 

[kentactic]

Re: Trust the level or the eye?

yeah its new to me... i thought i was able to level my rifle in the feild by eyeball and was horribly wrong. at 100 yards i was hitting 1 inch right in one terrain setting.. so i broke down and accepted the fact that i might need a level on my rifle.

 

[shoot4fun]

Re: Trust the level or the eye?

First, is it a USO bubble on the pic rail? If so, you might want to google search that for posts here. There was one recently about them putting out some levels that weren't right.
Also, I heard of guys using a plumb bob to verify the vertical crosshairs.

 

[redirt78]

Re: Trust the level or the eye?

Try holding the level on a construction type level and see if they match up. Take it with you next time you are near Home Depot or Lowes and just use one of theirs if you don't have one.

 

[kentactic]

Re: Trust the level or the eye?

10-4 guys ill confirm my level is indeed level.. although i heard that these rail levels only prove to actually be level when mounted to the rail... and its not a USO.. just some cheapy. (might be my problem)

 

[SavageStag]

Re: Trust the level or the eye?

Neve mind. I thought you were talking about mounting a scope, my bad.

 

[JuniperEyes]

Re: Trust the level or the eye?

Trees generally grow straight up

Buildings are generally built plumb

Light poles are somewhat straight up

A string with a weight on the end will always hang straight down

Scope base mounted levels are rarely correct

None of the above matters unless your scope tracks straight up and down when the crosshairs are level

 

[Graham]

Re: Trust the level or the eye?

Short of ELR work you really don't need a level.

 

[ggmanning]

Re: Trust the level or the eye?

I level the the scope with the bubble level on the rail and a level on the turret. I also check it with either a boresighter plumbed on the muzzle or a plumb line. Main thing is I want the scope level to the rail.....then if the reticle shows canted with rail leveled and looking at a plumb line the reticle is canted. Sent back a brand new scope a couple of months ago for the same reason. Finally, shoot it on a target to the same POA with a plumb line and dial up the elevation as you shoot a few rounds for a final check or dial the erctor looking at a plumb target or bore sighter grid. The erector should be perpendicular to the turret. As long as you level your scope matching your level on the rail it will be right shooting at distance even if the rail level is off a few degrees.

 

[tullius]

Re: Trust the level or the eye?

Install your rail level on the rifle. Put a known good (machinist's preferred) level or level rig on top of the picatinny rail to cross check your new rail level. Be sure they match, or note the offset & record.

Now hang a plumb bob with string thick enough to see @ 100 yds. Set your reticle to the plumb bob line, keeping the rail level.

Done.

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Short of ELR work you really don't need a level. </div></div>

well graham thats what i thought aswell perhaps your better then i am at eyeballing it.. because i was WAY off one time. i must have been atleast 5 degrees canted trying to eyeball it... what ever it takes to shift POI 1 inch right at 100 yards....thats how far off i was from level. the ground i was on was also slanted so it messed with my perception but never the less... no bueno...

after about three shots the same distance right i knew something was up and slapped a level on the turret, leveled based on that and i was back on target.

 

[tullius]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Short of ELR work you really don't need a level.</div></div>

Not true, especially when shooting off the side of a hill or mountain at a target on a backdrop that has nothing on it that's either plumb or level..

 

[Graham]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: tullius</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Short of ELR work you really don't need a level.</div></div> Not true, especially when shooting off the side of a hill or mountain at a target on a backdrop that has nothing on it that's either plumb or level.. </div></div>I'd like to hear that one explained in detail.

I've never used a level at ASC and I hit the targets just fine every year. In fact, I'll go one step further and say that even in ELR work you don't really need a level on your rifle. I didn't use one at Gunsite and I had a 33% hit ratio out to 1700 meters. I was just smitten with 33% hits - without or without a gadget.

 

[skep_tic1]

Re: Trust the level or the eye?

I wonder if that's why Horiuchi missed......... because he didn't have a level?

 

[Shady_Jay]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ~Ace~</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: skep_tic1</div><div class="ubbcode-body">I wonder if that's why Horiuchi missed......... because he didn't have a level?</div></div>

Sick Fucking Joke dude..... Way off Base. </div></div>

He was using magnetic level instead of grid level.

 

[kentactic]

Re: Trust the level or the eye?

ok guys... heres what i did...tell me if i gained anything..

i took the base level and leveled the rifle off of what the level said was level... i then reveresed it... flipped it to the other side... and it still said it was level... it would have to be true level to stay the same when reversed right?

 

[Evolution 9]

Re: Trust the level or the eye?

Yes, that proves the base level is level. Now do you still have a problem above that (scope itself being level)?


For what it's worth, I'm an LE sniper and I don't find the Horiuchi comment off base. Just MHO.



Someone took this wrong, so just to clarify, Let's just say I am NOT a big fan of Horiuchi.

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Evolution 9</div><div class="ubbcode-body">Yes, that proves the base level is level. Now do you still have a problem above that (scope itself being level)?


For what it's worth, I'm an LE sniper and I don't find the Horiuchi comment off base. Just MHO. </div></div>

well i leveled the rifle and lined up the reticle level off the corner of a neighbors house. i put a level on the turret and it still says its not level. im just going to shoot it like this and crank on the turret and see if it stays in line. if it dosent ill think about sending it back.

 

[mouse07410]

Re: Trust the level or the eye?

I'd say - your reticle is installed canted.

Set a plumb bob somewhere where you can focus the scope - say 30m or so, level your scope with the bubble level <span style="text-decoration: underline">or</span> align the reticle with the plumb bob rope. <span style="font-weight: bold">The main thing is to determine whether the scope - as installed - accurately tracks the vertical line.</span> No need to shoot the rifle to figure out whether the scope tracks or not.

Also, one can hit with a correctly-tracking scope even if the reticle is visibly canted - at the cost of inability to easily do holdovers.

 

[tullius]

Re: Trust the level or the eye?

Don't trust leveling off the top of the turret, go with the vertical off a plumb bob line.

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mouse07410</div><div class="ubbcode-body">I'd say - your reticle is installed canted.

Set a plumb bob somewhere where you can focus the scope - say 30m or so, level your scope with the bubble level <span style="text-decoration: underline">or</span> align the reticle with the plumb bob rope. The main thing is to determine whether the scope - as installed - accurately tracks the vertical line. No need to shoot the rifle to figure out whether the scope tracks or not. </div></div>

ok so now i know the rifles level off the base level...so i just level that to my plumb bob line and crank up and it should remain aligned and if it does its good and if not its no good. right?

but.... if the reticle is infact canted i wont realize that im also gaining windage as i crank up. it will remain lined up level but i will be adjusting the canted windage and wont be able to see it unless i shoot to see that my POA and POI are no longer on the same vertical line.

 

[patriotoutlaw]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: tullius</div><div class="ubbcode-body">Install your rail level on the rifle. Put a known good (machinist's preferred) level or level rig on top of the picatinny rail to cross check your new rail level. Be sure they match, or note the offset & record.

Now hang a plumb bob with string thick enough to see @ 100 yds. Set your reticle to the plumb bob line, keeping the rail level.

Done. </div></div>


+1

 

[Rob01]

Re: Trust the level or the eye?

Pretty much the same way I have done it for years and it has never let me down. I always verify at the range shooting on paper.

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[9H_Cracka]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Short of ELR work you really don't need a level. </div></div>

These well documented test results indicate otherwise.

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2189771

I swear my level is wrong most of the time, but logic and a 10th grade Physics class always leads me to trusting the level.

 

[Lofty]

Re: Trust the level or the eye?

Just used this last night on a new install.....works awesome!

http://www.brownells.com/.aspx/pid=6097/Product/EXD_ENGINEERING_VERTICAL_RETICLE_INSTRUMENT

It ensures that your vertical reticle line bisects the bore of the barrel perfectly so it doesnt rely on wether or not the surfaces on your scope or rifle are level.

When used with a plumb this thing is dead nuts on.

 

[223man]

Re: Trust the level or the eye?

Just a question. If your reticle is canted, would you not want to level off the scope its self and not the reticle? Because if you level off the reticle that means that your scope is not level there fore when you dial it will move the reticle in the direction that the now canted scope. But if you just level the scope and have a canted reticle, when you dial the reticle will move up and down true. Is this wrong?

ps. It is to my understanding that scope companies actually have something like a 3 deg of play room before they are out of spec.

 

[Evolution 9]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 223man</div><div class="ubbcode-body">
ps. It is to my understanding that scope companies actually have something like a 3 deg of play room before they are out of spec. </div></div>

That depends on the company. This is one of those, "you get what you pay for" things.

 

[notquiteright]

Re: Trust the level or the eye?

I must have missed something, why does everyone think a newly mounted scope being 1 inch off to the right means something is canted?

IF the base or scope is canted left or right then the verticle adjustment is off as well. Try running the scope up two complete revolutions and see if that gives a lower than expected come-up WITH a horizonal deviation.

 

[marduk185]

Re: Trust the level or the eye?

go to walmart. pick up two of the same levels. set them on top of each other and see if they read the same. my point is that many levels dont read the same. im way more confident in a setup being level if i can get the same reading with the same level from several different locations on the rail and the turret and its even better if that coincides with the way the rifle sits on the level surface from the bipod.

 

[mouse07410]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kentactic</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mouse07410</div><div class="ubbcode-body">I'd say - your reticle is installed canted.

Set a plumb bob somewhere where you can focus the scope - say 30m or so, level your scope with the bubble level <span style="text-decoration: underline">or</span> align the reticle with the plumb bob rope. <span style="font-weight: bold">The main thing is to determine whether the scope - as installed - accurately tracks the vertical line</span>. No need to shoot the rifle to figure out whether the scope tracks or not. </div></div>

ok so now i know the rifles level off the base level...so i just level that to my plumb bob line <span style="font-weight: bold">and crank up and it should remain aligned</span> and if it does its good and if not its no good. right?</div></div>
Yes. This is exactly how I'm doing it, and how I understand it.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">but.... if the reticle is in fact canted I won't realize that I'm also gaining windage as i crank up. it will remain lined up level but i will be adjusting the canted windage and wont be able to see it unless i shoot to see that my POA and POI are no longer on the same vertical line. </div></div>
I think that verifying that it correctly tracks the vertical takes care of this - as you won't be adding windage with vertical changes when the reticle faithfully tracks the vertical. And if it doesn't track - you'll see it, and will decide what to do from there.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: tullius</div><div class="ubbcode-body">Now hang a plumb bob with string thick enough to see @ 100 yds. Set your reticle to the plumb bob line, keeping the rail level.</div></div>
Good, but not good enough. It's not enough to just see the reticle "aligned" (parallel with and overlapping the plumb bob) - you must make sure it <span style="font-weight: bold">stays</span> aligned (not just "parallel to" the plumb bob - but keeps staying on top of it rather than moving sideways away from it) as you dial elevation in (and out).

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: notquiteright</div><div class="ubbcode-body">I must have missed something, why does everyone think a newly mounted scope being 1 inch off to the right means something is canted?

IF the base or scope is canted left or right then the verticle adjustment is off as well. Try running the scope up two complete revolutions and see if that gives a lower than expected come-up WITH a horizonal deviation. </div></div>

i never said the scope was canted itself... the entire rifle was canted... a canted rifle will shift POI in the direction of the cant.

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">i think that verifying that it correctly tracks the vertical takes care of this - as you won't be adding windage with vertical changes when the reticle faithfully tracks the vertical. And if it doesn't track - you'll see it, and will decide what to do from there.</div></div>


how could i see the reticle tracking out of alignment?.. if i line my reticle up on a plumb bob line and its lined up perfect... .. now if i crank up the elevation and look through the rifle again ill still be able to line it up vertically. theres no way i would notice a 1 inch shift or something like that because no matter how canted it tracks it will always remain vertically level as i crank the elevation.

 

[mouse07410]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kentactic</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">i think that verifying that it correctly tracks the vertical takes care of this - as you won't be adding windage with vertical changes when the reticle faithfully tracks the vertical. And if it doesn't track - you'll see it, and will decide what to do from there.</div></div>
how could i see the reticle tracking out of alignment?..</div></div>
Just trust me on this!

<span style="font-style: italic">We're from the Government, and we're here to help!

</span>

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">if i line my reticle up on a plumb bob line and its lined up perfect... .. now if i crank up the elevation and look through the rifle again ill still be able to line it up vertically.</div></div>
You line it up <span style="font-weight: bold">once</span>. Then you dial in elevation and observe whether the reticle <span style="font-weight: bold">stays</span> (a) aligned with and (b) overlaying the plumb bob. If something is out of whack - the reticle will stay <span style="font-weight: bold">parallel to</span> - but start <span style="font-weight: bold">moving away from</span> - the plumb bob.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">theres no way i would notice a 1 inch shift or something like that because no matter how canted it tracks it will always remain vertically level as i crank the elevation. </div></div>
Trust yourself now, and give it a try! You might be surprised. I found a reticle cant that was later measured by professionals as 1.5 degrees. I'm sure you can do as good.

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">You line it up once. Then you dial in elevation and observe whether the reticle stays (a) aligned with and (b) overlaying the plumb bob. If something is out of whack - the reticle will stay parallel to - but start moving away from - the plumb bob.</div></div>

ok ill try it but i think maybe the confusion is in whats not being said. are you sticking your rifle in some sort of a vice for this procedure? im just laying prone. once i come off the gun and adjust... any movement i see once i get back in the scope will just be marked up as me moving the rifle. im not that still to notice a hair line change in my vertical line coming off the plumb bob.

 

[mouse07410]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kentactic</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">You line it up once. Then you dial in elevation and observe whether the reticle stays (a) aligned with and (b) overlaying the plumb bob. If something is out of whack - the reticle will stay parallel to - but start moving away from - the plumb bob.</div></div>
ok ill try it but i think maybe the confusion is in whats not being said.</div></div>
Maybe.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">are you sticking your rifle in some sort of a vice for this procedure?</div></div>
Hell yes! The rifle gotta stay <span style="font-weight: bold"><span style="text-decoration: underline">motionless</span></span> during this process. I found that a good bipod and a rear monopod are good enough to hold it steady - a vice would be even better. Just being prone (with no rear support) could work but might be problematic...

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">im just laying prone. once i come off the gun and adjust... any movement i see once i get back in the scope will just be marked up as me moving the rifle. im not that still to notice a hair line change in my vertical line coming off the plumb bob. </div></div>
First, it's likely to be more than a hair line change if you dial in generously. Second - do "freeze" the rifle somehow, or the results are not going to please you.

 

[Graham]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: _9H</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Short of ELR work you really don't need a level. </div></div>These well documented test results indicate otherwise.
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2189771
I swear my level is wrong most of the time, but logic and a 10th grade Physics class always leads me to trusting the level. </div></div>Some people are advocates of using levels for long range shooting, others are not. Cory Trapp and Bryan Litz certainly do, and they are not wrong.

I saw so, so many levels on rifles this year at the 'Cup that the staging area looked like a bubble-level convention. But not once during the match did I see anyone effectively using a level. I refer you to the following posts in the Thread you mentioned above:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">I certainly wouldn't worry about the group size - the <span style="font-weight: bold">worst</span> of those groups is still around an MOA - and the best is about a third of an MOA, which is really nice shooting at 600 yards! I put those parameters into JBM Ballistics, and it pretty accurately predicts the lateral offset you shot - it calculates the effect of a 5 degree cant with that load at 9 inches, which is about midway between the two measurements of group center.</div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">I think for some people using a level can be useful, however I have to question someone who is attempting to level off anything but the target and what they see in the scope... I don't use a horizon either, as I wouldn't be looking at the horizon, I am focusing on the target... But if you do find you have difficultly, then by all means use the level. But I would look at your technique for aiming in hopes of moving away from the dependency. For the tactical shooter, they are not always available, as well not always visible. On a slow fire square range if you can squeeze that last ounce of accuracy out, sure but then again, you do get sighters. </div></div>
I don't deny that various test results show canting a rifle affects point of impact. But that's not the same thing as saying that use of a level is a necessity for the type of long range shooting that we do.

 

[9H_Cracka]

Re: Trust the level or the eye?

Denial ain't a river through Egypt.

 

[kentactic]

Re: Trust the level or the eye?

wont just cranking the elevation and shooting be alot less hassle i dont have any place to do a solid test like this other then at the range so i might aswell just shoot. im going tomorrow morning so im just going to Confirm zero, shoot at 100 yards, dial up 4 mills and hold on the 4th mil-dot and hold the same spot on the target at 100 yards and shoot again. if its anywhere but on the first hole i know ive got issues.

does this sound like a reliable test? the only down side might be its not enough adjustment to make the problem show its face.

 

[Graham]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: _9H</div><div class="ubbcode-body">Denial ain't a river through Egypt. </div></div>LOL!

Perhaps we ain't the shootin' jacket crowd.

 

[vman]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kentactic</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Short of ELR work you really don't need a level. </div></div>

well graham thats what i thought aswell perhaps your better then i am at eyeballing it.. because i was WAY off one time. i must have been atleast 5 degrees canted trying to eyeball it... what ever it takes to shift POI 1 inch right at 100 yards....thats how far off i was from level. the ground i was on was also slanted so it messed with my perception but never the less... no bueno...

after about three shots the same distance right i knew something was up and slapped a level on the turret, leveled based on that and i was back on target. </div></div>

My understanding is that once a rifle is zeroed, even if you are slightly canted you should not be seeing the results of cant at 100 yards... otherwise It would not be zeroed.

zero = zero... cant is the result of a tracking error beyond zero and is compounded more and more with the distance traveled vs the degree of cant.

Am I wrong?

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kentactic</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Short of ELR work you really don't need a level. </div></div>

well graham thats what i thought aswell perhaps your better then i am at eyeballing it.. because i was WAY off one time. i must have been atleast 5 degrees canted trying to eyeball it... what ever it takes to shift POI 1 inch right at 100 yards....thats how far off i was from level. the ground i was on was also slanted so it messed with my perception but never the less... no bueno...

after about three shots the same distance right i knew something was up and slapped a level on the turret, leveled based on that and i was back on target. </div></div>

My understanding is that once a rifle is zeroed, even if you are slightly canted you should not be seeing the results of cant at 100 yards... otherwise It would not be zeroed.

zero = zero... cant is the result of a tracking error beyond zero and is compounded more and more with the distance traveled vs the degree of cant.

Am I wrong? </div></div>

hm interesting.... what your saying is i could shoot the rifle at a 90 deg. angle and should still have the same POI result... makes sense. im not qualified to confirm this though. ill wait for responses.

 

[Graham]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">My understanding is that once a rifle is zeroed, even if you are slightly canted you should not be seeing the results of cant at 100 yards... otherwise It would not be zeroed. zero = zero... cant is the result of a tracking error beyond zero and is compounded more and more with the distance traveled vs the degree of cant. Am I wrong? </div></div>It depends.

First, have a look here: http://www.riflescopelevel.com/cant_errors.html

Now, if you cant the rifle ninety degrees, even at 100 yards, your windage will be your elevation (but it’s at zero) and your elevation zero is now your windage zero, but at about 1.25 Mils off the line of bore.

So, if you fire a shot at point of aim the point of impact will be about 1.25 Mils left because that is how far the scope is off from the line of the bore. And the shot will also be about 3/4 Mil low because there is no longer a sight height to compensate for since - with the rifle sideways - the scope is at the same level as the bore.

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">My understanding is that once a rifle is zeroed, even if you are slightly canted you should not be seeing the results of cant at 100 yards... otherwise It would not be zeroed. zero = zero... cant is the result of a tracking error beyond zero and is compounded more and more with the distance traveled vs the degree of cant. Am I wrong? </div></div>It depends.

First, have a look here: http://www.riflescopelevel.com/cant_errors.html

Now, if you cant the rifle ninety degrees, even at 100 yards, your windage will be your elevation (but it’s at zero) and your elevation zero is now your windage zero, but at about 1.25 Mils off the line of bore. </div></div>

so basically as the rifles starting to cant your losing some of your "zero adjustment" as it turns? and it loses more as the degree of angle increases?

 

[Graham]

Re: Trust the level or the eye?

If you ask the question that way it is possible to get lost in a definition of what a 'zero' is. The point is that one must understand the components of a short range zero and its reverse offset. Yes, if you are making a shot at greater than your zero range it gets more complicated, in which case I prefer a parrel-bore zero because it allows me to hold by the amount of the height of the sights over the bore and hold high by the amount of actual bullet drop.

...and still with no bubble level required on my rifle.

 

[kentactic]

Re: Trust the level or the eye?

well heres what i had happen. and then i "leveled" the rifle and shot again and i was dead nutts. these were shot at 100 yards and thats where my rifle is Zero'd for. (sorry one image is out of focus). am i insane or does this make sense and was likely a canted rifle issue?

 

[9H_Cracka]

Re: Trust the level or the eye?

This thread points out two facts Graham - one, cant has a real and measurable effect on POI, and two, a not insignificant percentage of our species displays disassociative behavior, regardless of background.

I'm no stranger to the sand flats of south Texas terrain.

 

[Graham]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: _9H</div><div class="ubbcode-body">This thread points out two facts Graham - one, cant has a real and measurable effect on POI, and two, a not insignificant percentage of our species displays disassociative behavior, regardless of background.

I'm no stranger to the sand flats of south Texas terrain. </div></div>As I said, I don't disagree that cant effects point of impact.

The rest of your post I'm not sure I understand: I wasn't talking about you, or where you have been, and we can agree that you are a much better shooter that I am.

 

[vman]

Re: Trust the level or the eye?

Graham, thats what I was thinking.

Kentatic, imagine this. Your rifle is zeroed perfectly and your scope is level.

Elevation adjustment move upwards in a perfectly plumb line. So, elevation adjustments are just that, 100% adjustment in elevation.

Cant introduces windage to the elevation adjustment by pushing that vertical line slightly to one side... The more the rifle is canted, the greater the angle on that upward travel, ie, more introduced windage. And that is why the further out your pushing the greater the effect on perceived windage, because your dialing more on that elevation turret.

For me to believe that your rifle is canted, you would have to tell me your zero is way beyond 100 yards (lets say 300), and that your dialing back to shoot at 100... at which point yes you have now introduced some windage by deviating from zero with a canted rifle.

Unless im totally wrong here with everything im saying, I think this is more a case of operater error than rifle cant.

What is the pull weight of your trigger?

 

[kentactic]

Re: Trust the level or the eye?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">Graham, thats what I was thinking.

Kentatic, imagine this. Your rifle is zeroed perfectly and your scope is level.

Elevation adjustment move upwards in a perfectly plumb line. So, elevation adjustments are just that, 100% adjustment in elevation.

Cant introduces windage to the elevation adjustment by pushing that vertical line slightly to one side... The more the rifle is canted, the greater the angle on that upward travel, ie, more introduced windage. And that is why the further out your pushing the greater the effect on perceived windage, because your dialing more on that elevation turret.

For me to believe that your rifle is canted, you would have to tell me your zero is way beyond 100 yards (lets say 300), and that your dialing back to shoot at 100... at which point yes you have now introduced some windage by deviating from zero with a canted rifle.

Unless im totally wrong here with everything im saying, I think this is more a case of operater error than rifle cant.

What is the pull weight of your trigger? </div></div>

id say around 3.5lbs...

im no stranger to operator errors so its deffinatly an option but that day those were the first three shots... then i leveled the rifle and every shot after that was on target. once i leveld the rifle i could not believe what was actually level compared to what i thought was level. and ive never seen this happen before. that was the first time id ever seen it shift to one side like that. and it hasnt since.

tomorrow im going to purposely cant the rifle to try and recreate my results. assuming the scope passes its leveling/tracking tests.