Scope differences at 100 and 200 yards left to right

Dan,
I was going to quit, but I think that I am going to try one more time. Call me a sucker for punishment! /ubbthreads/images/graemlins/grinning-smiley-006.gif
I have known for some time where you are going wrong, and have tried different ways of explaining it. Follow closely. /ubbthreads/images/graemlins/smile.gif From your first reference to offset and side mounted scopes it was obvious that you are trying to paralell the two paths. The reference to the muzzle or barrel not being under the line of sight shows the same thing. Well you can quit trying to explain that, because I get it. That is not the problem, but it is where you are going wrong. You could mount the scope 1 whole inch to the side and as long as you had the scope level, and the rifle level you could parallel the line of sight. Actually it would be aligning the vertical plane of the bullet's path with the line of sight because it is impossible to parallel a line with a parabola. Picture a sheet of plywood along side a clothes line.That model will work because your bullet will first rise on that plane, then fall back on that plane as gravity pulls it back down. You could get a welding buddy to build offset mounts and put the scope 3 feet or 3 miles off to the side and you would still be able to parallel the line of sight, AS LONG as both the scope and the rifle are vertical. The tiny bit of horizontal offset means nothing just like you say.(SO quit saying it!) /ubbthreads/images/graemlins/grinning-smiley-006.gif It isn't a problem and is not THE problem.
What makes a difference is that when you cant the rifle you introduce a horizontal element to the situation.The reason for that is because your barrel is not level, it is pointed slightly up. (You know that) As soon as you cant the rifle it is pointed up AND over to the side. It does not matter that is not laying straight to the side, there are relative amounts of sideways and that was figgered and charted thousands of years ago. That horizontal vector never goes away, it is immune to gravity, cares nothing for velocity. Just as a bullet can go forward and drop at the same time, it is now going forward, down and sideways at the same time.Now picture your sheet of plywood leaning at an angle./ / like that. The bullet when it drops cannot return on the same path because gravity can only pull straight down. Because it is still going sideways it will descend at the opposite angle \\ \\\\. Actually it would form a 3 dimensional curve, but nothing on this key pad looks right! /ubbthreads/images/graemlins/frown.gif
You cannot parallel a line with a curve, it is impossible, cannot happen, cannot be made to happen. You (The sighter) can make them intersect at one point,if the rifle is on a true vertical plane then gravity can make it happen again.
If the rifle is held straight but the scope is canted the bullet will drop straight down along its path. It will not follow the bottom cross-hair because the cross-hair is not vertical. If the crosshair are held level and the rifle is canted like you have said the problem changes to the bullet path curveing away from the line of sight, never to return.You cannot adjust sights to compensate for this curved bullet path, but you can set your windage at a midrange distance and split the difference in the error. It may not be enough to notice, and the effects of wind will hide or mask it too.
The effect is real, whether it matters to you is up to you. I, and most of the world prefer their scopes on straight. You apparantly don't care. That's OK, it's your scope, and your rifle, suit yourself. If you remain unconvinced so be it. You are still wrong /ubbthreads/images/graemlins/smile.gif And I'm done with this topic! /ubbthreads/images/graemlins/grin.gif We can argue about something else next time, until then:
Dogleg
 
Dan, The first thing I noticed from Climbers question was this was his first post. From that I gathered he may be new to the rifle shooting scene. I may have been wrong with that assumption. Only he can answer that. But with the assumption I made, I assumed he prob had the scope on the rifle canted to a certain degree. How many times have you had a guy with his first rifle that came up and said" Hey dude, check out my rig. you picked up the rifle and shoulder it. hand it back to him and tellhim his scope is "crooked". The scope is not crooked it is canted. He cant see it. I use that segway scope leveler everytime I mount a scope. It cuts down on a lot of arguments when a guy picks up my rifles and tries to tell me my scope is "crooked".

On a side note. I met the guy that invented and has the patent on the Segway scope leveler. He is an interesting fellow to say the least. I asked how he came up with such a simple design, that all the R&D guys from the big companies never came up with. He was with some guys at a deer camp, arguing about whose scope was level. This was with some really good riflemen. The point being, when a person mounts a rifle scope by leveling it to his eye while shouldering the gun, he will usually build in a certain amount of cant. Then if he goes out to the range and staples a target to the back stop with a small amount of cant. then lines up his scope to be square to the grids of the target, he can have a "cant windage deviation"(how is that for a made up terminology} and not even know it. I hope that climber guy gets his problem solved after reading all the post LOL.
 
Dogleg,

You wrote:

As soon as you cant the rifle it is pointed up AND over to the side. It does not matter that is not laying straight to the side, there are relative amounts of sideways and that was figgered and charted thousands of years ago. That horizontal vector never goes away, it is immune to gravity, cares nothing for velocity. Just as a bullet can go forward and drop at the same time, it is now going forward, down and sideways at the same time.

/ubbthreads/images/graemlins/confused.gif

The first part of that paragraph I must admit that I can't understand at all.

As for the last line, I don't accept the notion that the bullet path curves to the side (in addition to moving forward and dropping from gravity) by virtue of a canted rifle. The bullet will go up, and then drop, whether it is fired from an upright rifle, or a canted rifle--or even an upside-down rifle. It doesn't matter...

I think it's beginning to look good for the home team... /ubbthreads/images/graemlins/wink.gif

Dan
 
Dan,
Quote "The first part of that paragraph I must admit that I can't understand at all."
A lot of people cannot and do not understand geo-trig, never mind vector addition. You are not alone, admitting it is the first step. /ubbthreads/images/graemlins/grinning-smiley-006.gif

Quote" The bullet will go up, and then drop, whether it is fired from an upright rifle, or a canted rifle--or even an upside-down rifle. It doesn't matter...


It matters:

On an upright rifle the bullet will go up because it was sent that way and drop down due to gravity following the line of sight.

On a sideways rifle the bullet will go sideways and drop. Sideways because it was sent that way, and drop because gravity will not denied. Going sideways and down at the same time results in a 3-D curve.It cannot follow the line of sight.

With an upsidedown rifle the bullet will drop like a rock, because you have directed it downward and gravity is assisting. It will follow the line of sight as far as windage is concerned though

If a rifle is somewhere in between straight and sideways it canted and the results will be somewhere in between.It will have some of the characteristics of both. The bullet will go up first because to a greater extent it was sent there. It will go sideways (Or diverge laterally)because to a lesser extent it was sent that way too. Then it will drop like every other bullet in the world, but cannot stop going sideways. There is no other force to counteract it. This forms a 3-D curve also, it's shape determined by velocity, and departure angle. The amount of the sideways component is determined by what the cant angle is. That will determine what portion of straight sideways applies. This is not rocket science, young teens are taught this in school every day.

Why you would argue something that you admit you do not understand baffles me.A bullet can go forward, drop and go sideways at the time. So does anything thrown from a moving vehicle, although the reasons are different. Each action can be independant of the other, but the total effect is influenced by all of them. Did you know that a bullet goes up and down at the same time? Up because it was sent on an upward path relative to the earth, down relative to the bore line because the laws of gravity will not be denied. You don't have to understand all this to pull a trigger, any more than a race-car driver needs to be able to design an engine, to drive the car. You may be very good at pulling triggers, but you don't understand this part. You don't even want to understand it!
This thread was about climberguy and his rifle. You came up with a bunch of links that didn't apply to the situation, because your theory hinged on him running elevation clicks between 100 and 200 yards. Nothing wrong with the information mind you, but it didn't apply.

You know, I don't know for a fact that his scope is canted. Neither do you. Without the rifle in my hands, I will probably never know. It was offered as a possibility, you offered advice that could not help, because you were talking about something else.
When that didn't work out for you, you basically announced that everyone in the whole darn shooting world that wants their scopes on straight is wrong; everyone that is but Dan Newberry, "the apostle of the canted scope" and the only one that knows it doesn't matter. Now I'm a bit of contrarian myself, but when you are going against the tide you had best know the material inside out.

Question: Who the heck is the "Home Team"?



Climberguy,
I hope you get your rifle issues worked out. I know that if I had it in my hands it would be working already, and there are a great many other people that could do the same thing. Long distance diagnosis is tough, but a great policy is to start with the basics first.If it's basic and free so much the better.
I lent my Torx wrench to a fellow at the range today. His gunsmith mounted $2200 Zeiss was so far off straight that you could lose your balance looking through it. If you are wearing a wristwatch or have an analog clock close by, look at the minute marks.Each of those little marks and the resulting angle formed is 6 Degrees. 2 of them add up to 12 degrees. Some people can see that and some can't. Some that can see it will twist the rifle to level the cross-hairs so automatically that they are not aware of it.I can see 12 degrees of cant in a scope, 12 degrees on a rifle is a lot harder to see. That is why I asked at the beginning what other people thought when they looked through your scope.
Another thing you can try is to set your windage at a longer range, then work your way back to 100 and see what you get. Small sighting errors at close range magnify greatly at extended ranges. Now I'm not saying that that is the problem either, and since you are shooting 1/2" groups at 100 yards you must be doing something right!My rifles hold their windage at long range on calm days, so you are also doing something wrong. Let's just find it. Are you familiar with dialing out paralax? Ignore those range marking, just go for zero apparant movement. None of these things cost a nickel to check, so you have nothing to lose.
You'll get it. /ubbthreads/images/graemlins/grin.gif
Dogleg
 
Dogleg, I have been shooting rifles for over 20 years, but have never really concentrated on zeroing much past 100 years as the is about the longest shot you get around here where I live. I went out prairie doggin a few weekes ago and was making hits out to 400 yards pretty consistantly once i would get zeroed in from lobbing my aritlery at them. I figured out my scope was hitting left when I cam home and went to the range to try some 200 yards groups. I have always just eyeballed the scope to get the crosshairs set, and I must have got lucky with my other rifle as they are dead straight when I look at them in the mirror.
 
Dogleg... /ubbthreads/images/graemlins/laugh.gif That last post is a perfect example of the old adage "If you can't blind them with brilliance, baffle them with BS."

Some folks will buy it. Most won't. /ubbthreads/images/graemlins/wink.gif

Game, set, match...

Sorry.

Dan
 
I don't know that I want to get into this but I thought I might be able to help out a bit. This is interesting to say the least.

The first picture is a perfect setup. This is probably almost impossible to actually have, but it should help with this post.

Notice the center of the bore is directly under the center of the crosshairs.

The red line is from the bore and the green line is from the center of the crosshair and the shooter's line of site.

RiflenoCant.jpg


This next picture is a rifle with a lot of cant. Once again the red line is from the center of the bore (bullet path) and the green line is the shooter's line of site through the crosshairs of the scope. This will definitely cause problems the further downrange you go.

RifleCant.jpg


This last picture is I think what Dan is saying. Which the way he is saying it, he is exactly right. But, we don't sight rifles in so that the bullet path is parallel to the line of site. We site them in to hit the bull’s-eye at a certain yardage.

I think what he is saying is that no bullet comes out of the center of the bore perfectly and that we always have some alignment issues. He is right, but until we can figure out a perfect gun, we have to treat this as something we can't change. Sure it will cause some inaccuracy at long ranges, but we can't change that. So we must work with what we can change and that is why we try to mount the scope as square as possible.

RifleParrellelCant.jpg


I hope this helps and I hope I didn't mischaracterize anybody’s position on this. /ubbthreads/images/graemlins/confused1.gif
 
PWKing,

You got it! /ubbthreads/images/graemlins/laugh.gif

In your last depiction, if the amount of space between the red and green lines was only, say 1/4"--which would be about right for a rifle canted at 5 o'clock or 7 o'clock under a LEVEL scope--you'd only have that 1/4" of difference all the way downrange; it would not get any worse, and there would be no need to correct for windage at the various yardages you might shoot.

If you could shoot bugholes at 600 yards you could dial that 1/4" of windage to be perfectly correct at 600 yards. The scope line of sight and the bullet path would then cross at 600 yards. Then--you'd have to go all the way to 1200 yards to have the bullet be 1/4" off to the other side.

Obviously, the other factors affecting bullet path will have long, long since obscured this 1/4" of difference. You could even work with a 1/2" difference, cross it at 600 yards, and you'd never know it.

I think we've finally gotten somewhere. /ubbthreads/images/graemlins/laugh.gif

And your pictures are better than mine. I'm jealous! /ubbthreads/images/graemlins/blush.gif

I've gotta work tonite. I'll check back in on this tomorrow...

Dan
 
Albert,
I have to do five more of these wells before they let me out, but I usually get a standby day or two in between. It will probably take weeks to finish the total project. I would enjoy getting together, and if you see Rob tell him that I have arranged wholesale pricing for his steel 3 1/2"s.
Did Ted finish your 6BR?
Dogleg
 
Dan,
Once again you have forgotten a simple, obvious but vital factor of the equation.You still think that you can paralell the bullet path and the line of sight which is impossible, and I will show you why in terms, that anyone can understand. Today is your lucky day, or unlucky day depending on whether you want to learn or argue. Your choice.
Everyone that has ever sighted in a rifle knows that the bore-line is directed upwards through the line of sight, and drops back through it at a longer range. I expect nobody will dispute this, and I know that you won't.
This forms a right angle triangle, with distance between the line of sight and the boreline forming 1 side,the line of sight forming another and the bore-line or bullet path forming the third. Basic stuff.
Now what you can do, (You won't, but perhaps you can visualize it /ubbthreads/images/graemlins/laugh.gif)is take a carpenters square and tie a piece of string across the ends, forming a triangle. This will be the bore line, or bullet path if you prefer.It doesn't matter. The long side will be the sight-line and the short side can be the height above bore. Now pound 2 nails in a wall, at the same height. Hang the level with the short side hanging down, and push everything up nice and flush with the wall. You will see that everything, the two sides of the square and bullet path simulating string are all touching the wall, and that if the bullet were real it would follow the wall too. I don't think that there can be any dispute on this, everthing is on the same plane.The wall itself can be the vertical cross-hair.
Now, pull the bottom of the square away from the wall. Keep the long side of the square (which simulates our line of sight)against the wall. The line of sight will be unchanged because the wall didn't move. The vertical cross-hair didn't move because it IS the wall. The only thing that changed is that you introduced some cant into the system. Now look down the string. It is no longer paralelling the wall, it is now pointing into it!Try as you might, change walls, tear it down and build another one, the string is going to point at the wall. You can change the line of sight but the bullet will point up and across that one too. Once you have introduced that horizontal element into the equation it is never going away. If you aren't following this I bet that a whole bunch of other people can.
You would like the bullet path to parallel the wall? That can be done too, but not the way you claim. Assuming that you pounded the nails with the same amount sticking out, just slide the square out to the ends of the nails and let everything go. Presto, the square will hang vertically, and the string will again parallel the wall! There is some offset in the sytem, but as you pointed out that shouldn't be a huge problem. It just doesn't work your way. What we have just simulated is an offset scope with level crosshairs, on a level (Vertically oriented)rifle.

There's more. Since the straight, uncanted rifle is the real key to everything working, you could use a canted scope on a straight rifle. It sure would not be easy, but as long as you could hold that same tilt in the cross-hairs every time, and if the rifle was still straight up and down it would work after a fashion. The vertical and horizontal adjustments in the scope would not track precisely, and the bullets wouldn't fall along the axis of the vertical crosshair, but they would follow the line of sight. That is to say that they would drop under the intersection of the crosshairs. Wouldn't it just be easier to put it on straight?

You are the one who likes the sport analogies, so I am declaring this a TKO. You also mentioned B.S., it would seem that there is something on your face. Hard to say if it is of bovine origin though. /ubbthreads/images/graemlins/laugh.gif /ubbthreads/images/graemlins/laugh.gif /ubbthreads/images/graemlins/laugh.gif
Pound the nails, or go back to school. You're finished!
Dogleg
 
Dogleg,

I think the truth is that you actually realized at least one page back that my premise was correct.

You seemed to even say as much when you said: "If the crosshair are held level and the rifle is canted like you have said the problem changes to the bullet path curveing away from the line of sight, never to return.You cannot adjust sights to compensate for this curved bullet path, but you can set your windage at a midrange distance and split the difference in the error. It may not be enough to notice, and the effects of wind will hide or mask it too."

So, you realized at that point what I was talking about, but I suppose you have too much pride to say "Oh. I see what you mean--sorry for misunderstanding you in the first place."[/b]

PWKing has gotten it, as have most of the folks at 24hourcampfire: http://www.24hourcampfire.com/ubbthreads/showflat.php/Cat/0/Number/523836/an/0/page/1#523836

For the folks who understand the issue of paralleling line of sight and bullet path (parallel, yes, but only a tiny fraction of an inch apart in most cases) I need say no more.

I believe at this point in the debate, you have been reduced to hoping that those folks who remain confused about the issue will perhaps declare your "TKO" valid. /ubbthreads/images/graemlins/crazy.gif Great. Take 'em with you.

Those of us with understanding won't miss the entourage... /ubbthreads/images/graemlins/tongue.gif

Dan
 
Guys, from a simple cowboy's point of view, if the bore is 1/4" to the right of the bore; the POI at 100 yds is horizontally correct; then, at 200 yds, the POI should be 1/4" to the left. Not more!!
For a 2 1/2" horizontal deviation, due to cant, the rifle would need to be held horizontally, with a scope mount 2 1/2" "above" the bore.
Mark
 
Mark,

Since the bullet rises and falls a considerable amount from the muzzle to 200 yards, it's possible to cant the rifle severely enough to see the bullet fall aside 1 inch at 200 yards...

Take a look at this online ballistic calculator:'

http://www.mega.nu:8080/traj.html

You can change the wind to zero (from the default 10 mph) and then enter some degree of cant. Entering 12 degrees of cant with a 3600 fps 50 grain bullet with a .250 BC (which would have a similar trajectory to the one ClimberGuy mentions) shows that 12 degrees of cant, with a zero at 100 yards, would cause the bullet to fall about 1.3 inches to the side at 200 yards.

So that much is possible. As I've said a couple times already, however, 12 degrees may not sound like a lot of cant but if you'll simulate it with a scope in your hand--it's pretty noticeable.

Dan
 
Dan Newberry,
You neither drew the triangles nor pounded the nails did you? /ubbthreads/images/graemlins/smile.gif Not that I ever thought that you would.
Your mind is made up, and you don't want to be bothered with facts.
When I wrote about sighting at a midrange trajectory it was to show what the best way to minimize the damage was, and to show a knowledge of the material. It was not to agree that a bullet from a canted rifle can parallel a sight path. I have shown how that cannot be done.(Canted) And shown how it could actually be done.(Offset)There is a certainly a relationship between the two, because in this case the bore is offset because it is canted, and of course the rifle is canted just because it is canted. The small amount of offset is meaningless by itself.It is a fraction of even a small caliber bullet width,and it has been proven that scopes that are side mounted work OK.They work when the rifle is square and if you don't care if your scope adjustments work correctly they will even work with a twisted scope on a plumb rifle. As long as you don't expect the bullet drop to track the lower crosshair,you don't expect the elevation and windage adjustments to work independantly of each other, and the rifle is still straight up and down it will work. A dot recticle works fine without any crosshairs at all, but if it is not straight it will not track.You should find nothing to disagree with here, because this is what you are saying. No argument from me either.

Now that we have found common ground, quit thinking about it!Offset is not the problem, and never was. The entire issue is because of the cant in the rifle, not the offset that it causes. You really should build that model, it will show the concepts simply and vividly. (you won't /ubbthreads/images/graemlins/smile.gif) You could even use the model to show how a mythical (but badly wanted LOL)600 yard bughole rifle could benefit from merging the two planes together over a long distance. You could only do those things when the boreline is vertically oriented though. The problem is that the cant induces a horizontal element, it makes the string (bore line, bullet path,whole bunch of bullet pathes averaged, take your pick) point to the wall. The model could also be both offset and canted, but the problem once more is not the offset, it is that the rifle is now cross-eyed!!! The line of bore (Bullet path,whatever)crosses the line of sight and continues on that vector forever. Your solution to a cross-eyed person's delima would be to go up to him and say "you wouldn't have a problem if your eyes were just parallel!" Like he didn't already know that!
My solution to a cross-eyed rifle is simple, loosen 4 screws and eliminate the problem forever! Why anyone would think that a compromise "bandaid" sight setting, partial fix might be preferable to that is baffling. You cannot parallel the path, that is impossible. Best case is that you could split the difference, giving up some error on both sides. Why would you want to? Why would you settle for half an error when you can have none?
I had to check out the Campfire, a great place, always has been. There is an experience range there from green to "off the chart" gun greatness. I don't know what you see there, but I see one guy that cheerfully admits to not being able to level his scopes,one of a character analysis and religious message (lets call that one sincere but inconclusive)There are also posts by people that show a good working knowledge of cant induced crossfiring, the difference between cant and offset(Thats the part where you stall) and the effects of both.Some know the effects of both twisted scopes on straight rifles, and verticley aligned scopes on canted rifles, and how it would effect POI adjustments. All in all I find little to disagree with there, and can show you where I have said most of the same things. One thing that I didn't like about the thread is that 3/4s of it was you agreeing with yourself "Wizard". Perhaps a reading comprehension course, along with that math course might be in order.

This thread, once again, is about climberguy and his windage issue. I offered an observation and a possible solution. You offered:
Quote
"If you are to tell me that the shots are moving to the right at 200 yards without a scope adjustment I'm going to have to say "you've got me there." I can see no possible way that would happen with a conventionally mounted scope."

When you questioned the validity of my answer, and questioned its very possibility, I offered mathematical proof that it was at least possible, and not particularily unlikely. (whether you can understand the proof is immaterial)There is no way that I can prove that my opinion is climberguy's solution, all I can do at this moment is prove that it might be. I am pinning a lot of hope on climberguy's shooting test, and shooting ability. If that big, bad Savage vindicates me, great! More importantly if that Savage starts behaving itself, I will have helped someone and contributed to a hobby that has been a lifelong passion. If it doesn't help I will have done no harm, unless buddy turning 4 screws is harmful! /ubbthreads/images/graemlins/grinning-smiley-006.gif If some of the 11,000 members also feel the need to level their reticles there is still no harm done. I offer hope, you offer Quote "you've got me there." and critism.
I have managed to kill several hours on this post that would otherwise has been spent watching trees grow in this godforsaken drill camp.It's been fun, what would I have done otherwise? "you've got me there." /ubbthreads/images/graemlins/confused1.gif Now you got me doing it! /ubbthreads/images/graemlins/grinning-smiley-006.gif
Dogleg
 
Dan,
Quote "As I've said a couple times already, however, 12 degrees may not sound like a lot of cant but if you'll simulate it with a scope in your hand--it's pretty noticeable."

Actually that is correct, as far as it goes. The biggest part of the problem is not exactly that the scope is canted, it is that 12 degrees of cant will very likely lead to 12 degrees in the rifle when the shooter twists it to vertically align the reticle. 12 degrees is the same amount as 2 minute marks on your wrist-watch. It is noticeable in a scope, and when many people mount their rifles they level their reticles automatically. The problem becomes a apparently level reticle on a 12 degree canted rifle. The shooter saw the error and "fixes it" 12 degrees is not nearly as noticeable on a rifle and the stage is set. Canted rifles are what causes cross-firing, and to a great extent canted scopes lead to canted rifles. That is the crux of the problem.
Dogleg


By the way, it wasn't that long ago that you claimed that the error couldn't be caused by less than laying the rifle on it's side! Was that yesterday or the day before? Gotcha!It appears that you may have learned something after all, and in spite of yourself! Of somewhat lesser importance, you are now using a ballistic calulator to compute cant error? I've been calculating everything in this discussion by hand and in my head, which is not that difficult since I learned of it's existance long before yesterday.!!!!! Har Har Har!!!!! You crack me up.
 
At the risk of being flamed and called names, because I think you guys are about a step away from name calling, I will throw my .02 in at this point.

Dogleg there is a problem with the model you just described. The relationship between scope height (the short side of your carpenters square/triangle) and bore (the long side), do not determine bullet path (the string or hypotenuse of your triangle). When you lift the short end of the square away from the wall, to simulate cant, you do not induce a horizontal element into the bullet path. You don’t get that bullet path pointing into the wall because the string doesn’t get to move with the short end of the square. That end of the string is held by gravity, and the relationship you described is only true while the short end is normal to the earth.

If you have an absolutely bare barrel pointed down range, and marked 12 o' clock, fired, then rotated the barrel so that mark is off some amount, say 12 degrees, and fired again, bullet path has not changed. Gravity is still pulling straight down.

I do see your contention that line of sight and bullet path diverge after crossing at some sight in point (say 100 yards), and I also believe that making bullet path and line of sight completely parallel could be more than a little tough. But I think in reality and practicality the numbers don’t actually add up to enough to really really matter. With a 1.5 inch scope height and a radical 12 degree cant (that really is a lot) and a 100 yard zero you are off just under an inch at 400 yards. Thing is, cant is probably smaller than that, and we might just be sighted at 200(or beyond) and suddenly we are off less than half an inch, and that inch we were talking about is a lot further out, out there at ranges where we have bigger problems like wind and our admittedly limited ability to hold on target.

Still, every little bit helps, and it doesn’t cost all that much to eliminate this variable, the price of an inexpensive tool and a few shells at the range. I thought part of the explanation I read at the scoplevel website was very interesting, and I might just go to the range and see what happens at 100 yards as I dial the target turrets up in bigger increments than I have tried at that close range. I won’t be pleased if poi shifts a lot.
 
Remember that ClimberGuy said: "I am not messing with my windage or elevation settings. I am sighted in dead on at 200 and about 1 inch high at 100. At 100 I am dead center, and at 200 the bullet is hitting about 1 1/2-2 inches right. "

So. We have a dead center, 1" high hit at 100 yards, and we have a 200 yard hit with the elevation correct, but windage off 1.5 to 2 inches right?

According to the JBM ballistic calculator, you'd have to cant the rifle between 15 and 20 degrees to get the 1.5 to 2 inches of lateral error at 200 yards. If ClimberGuy's windage error truly is a matter of a canted scope, I will give him the benefit of the doubt that he canted right a few degrees for the 100 yard group, and then left a few degrees for the 200 yard group--because I still contend that there is no way a man wouldn't notice even 10 degrees of cant--not to mention 15 or 20.

Too, we cannot dismiss the possibility that ClimberGuy's scope may have moved zero, or there could have been a wind issue he didn't notice. These things happen to all of us--I'm sure we'll agree.

NWVH wrote: "When you lift the short end of the square away from the wall, to simulate cant, you do not induce a horizontal element into the bullet path."

I told Dogleg the same thing a few posts back when he said:

"Just as a bullet can go forward and drop at the same time, it is now going forward, down and sideways at the same time."

And then I said:

"...I don't accept the notion that the bullet path curves to the side (in addition to moving forward and dropping from gravity) by virtue of a canted rifle. The bullet will go up, and then drop, whether it is fired from an upright rifle, or a canted rifle--or even an upside-down rifle. It doesn't matter..."

But this whole matter has morphed away from being about what scopes and rifles and bullets do and don't do. We should be more concerend about learning and getting the truth out there than with stubborn matters of pride. /ubbthreads/images/graemlins/wink.gif

And toward that end...

Paralleling the scope's line of sight with the bullet's path is really no big deal. I'm sure that some of you have already "gotten it."But for those who may still be unsure...

bulletbarrelscope.jpg



Dan
 
nwvh longhair,
There should be no risk of name calling from me, though you could easily be right, tempers and frustration being what they are.LOL
It seems that you may have some misunderstanding of my model. I see 2 possibilities here, 1 likely and a second that is possible but not very likely. You have named the long side of the square the bore line, where I was using it as the line of sight. The string is the bullet path though,and also the bore line.(As a concession to Mr. Newberry I'll add"in a general sort of way") If you try to visualize it again, with that correction I think you will see it my way! In fact I know you will.It is encouraging to find some-one familiar with the term hypotenuse.

The second possibility is that you are looking at the model from the wrong end. It is designed to have the short leg toward you, with the long side being the line of sight and string (hypotenuse) showing a bullet sent on it's upward departure angle. All angles being exagerated of course! That would explain why you are using the short leg as a gravity factor when I didn't mention gravity at all in the simple model. This second explanation would make sense if you are looking at a horizontal bore-line with a bullet dropping away from it.It would also do nothing to prove my point, as you pointed out.
Let me know which one it was, or if it was just a typing error. This is more curiousity than anything now, because my shortlived "time to kill oportunity" is over. I will continue to want my own scopes on as straight as possible, knowing that it can do no harm, and believing that the opposite can do some harm. I expect that most shooters feel the same way, some don't know one way or the other, and some don't care. I have chosen my position, you have chosen the same one. (Straight scopes)That we assign differing amounts of importance to it is fine.
Hey, you didn't even need your flame suit! /ubbthreads/images/graemlins/smile.gifI was considering wearing my Nomex while typing, but instead will don them and get some work done. Playtime is over.
Dogleg
 
Dogleg,

That last post is nice. I'll set aside my "stubborn pride" and we'll leave this thing be...

I agree that putting the scope on straight is a good thing, and if I've ever mounted one with a cant it's not because I meant to do it. /ubbthreads/images/graemlins/blush.gif

We both agree (I think) that the amount of error is negligble in most cases and again, we also agree that a straight scope is better than a crooked one.

I realize that by nature of the business you're in, you have a drive to "make it perfect." Not a bad thing.

If I've become too agressive in my zeal to "drive my points home" I hereby apologize. I said "if" I've become too agressive--but I think there's no "if" too it. I have. /ubbthreads/images/graemlins/blush.gif

I hope both of our perspectives have contributed to a better understanding of this matter for the folks who have been reading along. (And there are many, judging from the view count).

Our differences here are, in retrospect, of a minor nature--and of relatively minor significance to the "big picture" of hitting what one is shooting at. /ubbthreads/images/graemlins/wink.gif

Dan
 


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