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Rifle cant, scope cant and counting horses teeth |
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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Posted: April/20/2008 at 11:09 |
Three Arabs were sitting in their tent, debating how many teeth a horse has. The first two had great theories, but different answers. Whilst they were debating, the third one quitely slipped out of the tent, and upon his return annouced "40". How do you work that out and what is your theory? they ask. I went to the stable and opened a horses mouth and counted them!
Well, today I counted horses teeth and a canted scope does not matter, as long as the scope reticule has not been altered after zeroing. Scope cant does also not cause the POI to move left or right of the vertical as long as the scope reticules was horizontal to the earths horizontal when pulling the trigger even if the rifle is canted under the scope. At 100 yds anyway.
Shots 1-4 zeroing the scope. Shot 4 being my accepted zero. (Minor scope adjustments between shots 1-4). Rifle horizintal, scope horizontal.
Shot 5 Scope and rifle canted 45deg to right.
Shot 6 Scope and rifle canted 45 deg to left.
My own opinion is that these POI (Shots 5 and 6)are left and right due to difficult shooting angles and holding of the rifle. You decide for yourself. And please shoot your zeroed rifle leaning it left and right and let us all know the result.
Shot 7 Rifle level, scope canted 45 degrees.
Shot 8 Moved the reticule 24 clicks up. Canted the rifle 45 deg left, which brought the reticule horizontal with the earths horizontal.
Shot 9 Moved the scope from 45 deg to 22 deg of vertical. Canted the rifle 22 deg left, which brought the scope reticule horizontal with the earths horizontal
Shot 10. Moved the scope 0 degrees off vertical. Rifle level, scope level.
Edited by 8shots - April/21/2008 at 03:37 |
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sakomato
Optics Master Joined: February/28/2008 Location: Houston Status: Offline Points: 1166 |
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Hey 8shots
Can you post pics? Would make it a lot easier to understand.
The problem is that even if you rotate your scope then you may compensate and relevel the reticle by slightly canting the rifle. As long as your reticle is level then you will not experience the problems we have been going through on the other threads. But if you crank elevation and shoot with the reticle off level even 6 degrees (one minute on the clock face) then the POI moves left or right depending upon which way it is off level.
Here's some more reading that will or
I guess if we were into horses as much as we are into guns and scopes the number of teeth a horse has would be of grave, grave concern!!
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Guns only have 2 enemies, rust and politicians
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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Sakomato,
I could for some reason not post the pics yesterday (website problems?), but here they are.
My experiment was to prove or disprove the earlier discussion that stated: You can check if your scope is canted by zeroing your rifle, drawing a vertical and horizontal line, then dial your reticule up and make sure your scope reticule is on the lines you have just drawn. Fire another shot. If your scope was canted to begin with, this shot will now be left or right of the vertical line.
I argued, and now proved, that this is untrue, as one is simply rotating the scope and rifle around the same center point.
Altering a reticule on a canted scope and shooting it in the canted position will move your point of impact. This is something that stands to reason as your reticule will move left (or right) as you dial it up. This argument was never entered into during the previous threads. The discussion was all around rotating your scope to keep the reticule level, and if that will move your POI left or right.
See my shot 4 and 7. Shot 4 is scope zeroed, refle and scope level. Shot 7 is with the scope canted 45 deg! No changes was made to the scope setting, it was merely turned 45 deg. Rifle level, scope turned 45 deg!
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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Sakomato, I have read the link you have posted. My test proves exactly what the writer is saying. This is also what I have been arguing all along.
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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I would further say that any test that requires you to shoot the rifle, is full of problems as many variables come into play. Shooter ability, rifle and scope abilty, climatic influence and so on.
So if you want to level your rifle and reticule, do it with a spirit level of some sorts.
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Rancid Coolaid
MODERATOR Joined: January/19/2005 Location: United States Status: Offline Points: 9318 |
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I agree - kinda. The post that one could verify cant in this way is completely wrong: with that, I agree. Your process, though elaborate, proves one thing for certain - and something almost every southern US redneck knows: at close range, you can hit things with a really screwed up rig. The longer the distance, the more cant matters, and it cannot be effectively diagnosed without mechanical help (and a plumb line hanging in front of a rifle that may or may not be level ain't gonna get it done.) Add to that the fact that a perfectly leveled scope on a leveled match gun in the hands of an expert shooter with match ammo will almost always fall on either side of a straight line (but shouldn't fall far from the line, if the point of aim is on the line.) Nice setup, though, more work into it than I would have done. |
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sakomato
Optics Master Joined: February/28/2008 Location: Houston Status: Offline Points: 1166 |
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Hey 8shots
I don't believe we were ever really arguing in the other threads and nothing in those threads go against your findings to my knowledge. The premise of the shot POI's moving off the vertical when cranking elevation were if the reticle was not level but either rotated or off vertical because of rifle canting.
Your shots #8, #9 and #10 were taken with the reticle level. As I said in the other thread it doesn't matter if the rifle is canted if taking shots at 100 yards as long as the reticle if level. But if you shoot with the reticle off level after cranking elevation as you did not do then that is when the shift left or right should show up.
You counted the teeth on the wrong horse!
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Guns only have 2 enemies, rust and politicians
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snowflake77
Optics Apprentice Joined: March/19/2008 Status: Offline Points: 66 |
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Way over my head but hopefully after a few months of reading posts like this it may sink in. Really good stuff you guys are doing here and I would like to thank you for your knowledge.
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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Sakomato, I meant "discuss" by using the word "argue".
And this was the horses teeth we were counting: (Question Posted my someone else)
I know somewheres I saw a thread/video on rifle canting(rotational drift) and how to correct for level a mounted scope’s reticle. I’m unable to find it now..Something like drawing a target plumb line and making sure its perfectly plumb with a 4’ mason level. Then take aim at 50 or 100 yds(I’m unsure what’s most efficient), making sure to keep your elevation reticle is perfectly parallel to the target plumb line you just drew on the target. Fire the shot,(assuming it’s a ‘good’ shot), if it ends up right or left of the plumb line, you know your rifle is canted and have to adjust . If its dead on center or very very close then no adjustment necessary. If POI is off, rotating scope to the side of the POI. Now, I’m a little confused on how much rotation is needed but I assume it’s in 1/16” or 1/8 or ¼ “ increments something like this – sort of trial and error with follow-up shots. CAN SOMEONE PLEASE GIVE ME THE LINK TO THIS VIDEO OR let me know how close I am in my description. thanks (ps. I prefer this method over any ‘gadget’ that can be bought) (pps. I know there is a way to level your scope using a line level on the receiver, then lay the level on the top of the scope but I’m not sure I trust this method. . anyway there is little horizontal ‘flat’ area on my receiver so that I can make sure the rifle is level) thanks .. pps. if this is a little long-winded, IT IS.. out.[/QUOTE]
And this was my reply:Sorry bro, this does not make sense. It could be shooting left or right because the scope is not zeroed. Maybe if you cranked the dial all the way down and then zeroed the rifle at the bottom of the target and then cranked the elevation all the way up again. At this point keep your elevation line plumb (you would need to have a few on your target to find one to plumb up to. Then fire a shot. Did it move left or right?
I do also think that rifle cant will not show up at such short distances. I think you need to go out to 800yds+
Then the variables, was it the scope with poor tracking? Was it the shooter, rifle?
Sorry cannot help with video (Also took me a while to get to the answer Edited by 8shots - April/22/2008 at 02:31 |
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sakomato
Optics Master Joined: February/28/2008 Location: Houston Status: Offline Points: 1166 |
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Yeah, I see what you mean. But I was thinking about all the posts that came after that in which seemed we came to the conclusion that a level reticle was the most important thing whether the rifle was canted or not. [/QUOTE=sakomato] The article really deals with scope rotation and not rifle cant. Scope rotation will have a different effect on the whole matter than rifle cant. Imagine an extreme example of scope rotation where the elevation turret is actually at 90 degrees or straight out to the right on a horizontal. Then when you dialed the elevation turret and then recentered your point of aim, the points of impact would be traveling the horizontal line. Of course that is a severe case but it illustrates the point.
The problem with scope rotation will more readily reveal itself with shooters who crank elevation but I believe that even with just a holdover it would be a problem because with a holdover you run the vertical reticle down through the target. If you do that and the scope is rotated then running the verticle retical down through the target will shift POI off vertical.
Also, if you cant your rifle but the verticle reticle is straight up and down as you hold the rifle in the cant, you will not have a problem. That is because cranking the elevation or holding over with a straight up and down verticle will also move the rifle in a straight up and down movement and your POI's will be straight up and down.[/QUOTE]
So for the shots where you cranked elevation I wish you had rotated the scope off level and seen if that made a difference in the POI's. Especially since you have such a good shooting rifle and range. |
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Guns only have 2 enemies, rust and politicians
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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Sakomato, I did not test the situation of a canted scope held not level and dialed up or down, as it most certainly will shift the POI to the left or right of the vertical.
I really just wanted to prove or disprove the original theory.
I certainly got myself all tied up trying to outthink what would actually happen, hence the effort of actually shooting the rifle to see how it all works out.
For the sake of completing this excercise, I will shoot my rifle with a canted scope zeroed. I will then dial up, keep the reticule canted, in other words the rifle will be held horizontal, and show you the result. I will do it this week-end.
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Charlie-bolted
Optics GrassHopper Joined: February/26/2008 Location: USA Status: Offline Points: 49 |
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A horse is a horse of course of course http://www.longrangehunting.com/articles/reticle-perpendicularity.php -here’s the article I was searching for.. finally ran across it ..for what its worth. .. Its been a long time since I was a pony
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some days we just get stuck and bogged down, Some days all u can do is smile and wait for someone to kindly remove your butt from the hole you find it wedged into.
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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We have seen this article and discussed it. This article is incorrect, as poven by my shooting and target posted. My reticule was canted 45 deg and should have been way off the vertical. Where this dude misses it, is that the rifle should be kept level, the elevation cranked up and then shoot with the rifle still held horizontol, NOT THE SCOPE. This will show up a canted reticule.
I will do this type of shooting this week/end and post the target.
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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I was under the impression you were searching for a video, so I did not highlight the link you are referring to. I am sure this dude got mixed up or mis printed, but his description is wrong.
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