Plum lined my vortex razor HD 4.5-27 and threw an accuracy 1st bubble level on it. Leveled the rifle first too. When I get behind the rifle the reticle looks ever so slightly canted counter clockwise. Re did it and same. Am I losing my mind or Is it bc of the cant in my head on the cheek weld??
Rifle Scopes Canted reticle after plum line or am I crazy
- Thread starter Lucreau
- Start date
Don’t level the rifle first. Just hold it how it naturally holds then plumb line the reticle to that position.
This. Only would add that you should set the scope-level level to the reticle (e.g., when it’s aligned with the plumb bob) and not to some other level set on the rifle (which would be pointless).
Best way to do this to just tighten down the bipod once the rifles in it’s comfortable position?
If I have a spuhr mount, should I level it first before plum-lining the scope? I have a problem when I level the Spuhr bubble level first then level the scope reticle to the plum line (hung in-door and using a DFAT). Then I look out the window point it at my neighbor's door frame across the street with the spuhr bubble leveled and the reticle is definitely canted. So either my neighbor's doorframe is canted or there is something wrong with the way I'm leveling my scope.
Personally, I just mount the scope the all the same in a spuhr and the bubble level is going to sit where it sits. Where it sits still provides as good enough of a reference point if I choose to use it.
At least for me, if I lined the bubble level up perfectly between the lines straight back off the rifle to set it up and later only check it from the side of the rifle if I check it at all, it’ll look off anyways (and then I might be temped to tilt the rifle to position the bubble to what looks like center from that viewing position if I’m second guessing my eye which only ends up canting the reticle instead). It’s possible that’s what you’re doing.
I have one rifle that the setup is the same way.... as I was building it up to get the height correct it also built up on the sides and now my head is leaned more than it should be. A easy way to test that is to get behind the gun left handed-- and it will appear as if the scope is tilted the other direction. And then figure out how to adjust (or replace) the cheek piece to get your head strait.
Honestly, I think the only way to really know if a reticle is canted is to strap the scope down to a stationary test bed facing a test target and run the adjustments over a large portion of their travel so that you can see if they are tracking in exactly the same line as the reticle.
I have been mistaken in thinking scopes had canted reticles by feel or even with cheap levels. Feel is subject both to experience and also allergies messing up your sense of balance. This is a frequent problem for me and others. I remember Regina talking about it not long ago. Just the other day I could have sworn my Uncle's scope was at least a degree off but I later strapped it down, tested it, and it was spot on. I shouldn't have been surprised. I frequently could swear this or that scope of mine is canted when I know damn well they are not. Allergies will mess with your mind.
In the case of most scopes with canted reticles, you are talking less than 2 degrees so it is pretty easy to induce larger errors using an imprecise measurement arrangement than the scope itself has.
I have been mistaken in thinking scopes had canted reticles by feel or even with cheap levels. Feel is subject both to experience and also allergies messing up your sense of balance. This is a frequent problem for me and others. I remember Regina talking about it not long ago. Just the other day I could have sworn my Uncle's scope was at least a degree off but I later strapped it down, tested it, and it was spot on. I shouldn't have been surprised. I frequently could swear this or that scope of mine is canted when I know damn well they are not. Allergies will mess with your mind.
In the case of most scopes with canted reticles, you are talking less than 2 degrees so it is pretty easy to induce larger errors using an imprecise measurement arrangement than the scope itself has.
1: Level the rifle. (This is the hardest depending on if there are any places to get an accurate reading of). Spirit level on picatinny rail probably is the best bet.
2: place scope in rings and (without disturbing rifle) make crosshairs level with vertical line. Flashlight through objective and a laser cross level thingy is a good way.
Main goal is to have the scope sightline directly above rifle bore.
2: place scope in rings and (without disturbing rifle) make crosshairs level with vertical line. Flashlight through objective and a laser cross level thingy is a good way.
Main goal is to have the scope sightline directly above rifle bore.
Please explain how it doesn’t matter. My logic may be off but this is how I have understood the importance of level scope and rifle.
To exaggerate, if I were to cant my rifle 45 degrees left (practically moving my scope left of the bore), and setting the reticle dead level.
I would have no problems zeroing the scope but shots closer than zero would end up to the right and shots further would end up to the left of my point of aim.
To exaggerate, if I were to cant my rifle 45 degrees left (practically moving my scope left of the bore), and setting the reticle dead level.
I would have no problems zeroing the scope but shots closer than zero would end up to the right and shots further would end up to the left of my point of aim.
As long as the vertical stadia is vertical, and assuming it tracks, the orientation of the gun makes no difference. You could hold the rifle 90 degrees, providing the vertical stadia was vertical. Gravity doesn't care how you hold the rifle.
The sine and cosine of 45* are root(2)/2, which is about .7, so if your sight height over bore was 2” you’d end up with approx 1.4” sight height and a lateral offset of 1.4.” If you ignored that lateral offset, your error at 1000y would be the distance, 1000y, divided by the zero distance, say 100y, minus 1, i.e., 9, times the offset, so approx. 13 inches.
If you corrected your windage at 200y it would be <6,” correcting at 500y it would be 1.4”. If you simply zeroed 1.4” right then all you’d ever end up with is a 1.4” offset carried out to infinity.
But you’re probably not tilting the rifle 45* (though you easily can and correct for it), it’d probably be more like in the range of 1-5*.
Take the max at 5*, the sine of which is .087, so if your height over bore is again 2”, that lateral offset is .174, which if you perfectly zeroed at 100y, would result in 1.566” of error at 1000y. If you tilt your rifle into your body (yielding a clockwise scope rotation to level for a righty), it simply cancels out a bit of spin drift. So when I say it doesn’t really matter, are all your calls, zero, and form good enough that 1.5” at 1000y would cause you to miss? It’s <.05mils, so I doubt it, as you have a decent enough chance of zeroing with less refinement than that.
To me Plumb reticles always look canted.
Maybe my mom dropped me in my head as a baby???
If I look over the top of the turret I can easily get the scope level on my rifles without levels.
Maybe my mom dropped me in my head as a baby???
If I look over the top of the turret I can easily get the scope level on my rifles without levels.
Comparing all of these as being the same without discussing the magnitude of the error induced is pointless. Not to mention that several of the examples are incorrect. A bullet’s travel can’t be mapped to a diagonal line (see the four examples on the far right) because it’s accelerating down due to gravity and decelerating in it’s direction of travel at the same time, so it won’t be “on” — not to mention that any dialing of the scope or use of the stadia in those conditions is completely disconnected from the reference frame of the forces acting on the bullet.
By all means though, use this as your gospel, or you could open up a high school geometry textbook and apply some common sense. Your choice.
If you level the scope to the rifle bore and then start holding the rifle crooked 5* every time you run the bolt after you touch off a shot because it’s more comfortable to hold it that way and forget to babysit your level you’re going to be feeding the berm at 1000y because you’re going to be off by a foot+ instead of 1.5”.
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Common sense for me is to try my absolute best to mount my scope having the vertical line in the crosshairs to intersect the bore of the rifle. Saying that it “doesn’t matter” is simply wrong.
This is where the discussion started.
Might be some miscommunication due to language barriers but I’m having a hard time believing you just randomly throw your scope in the rings and call it good.
This is where the discussion started.
Might be some miscommunication due to language barriers but I’m having a hard time believing you just randomly throw your scope in the rings and call it good.
What he is saying is the scope’s relation to the bore is not nearly as relevant as the scope’s relation to gravity.
For the sake of clarity, I’m referencing your illustration by numbering the examples left to right, top to bottom, starting at 1, and ending at 9.
It has been observed by the faculty of Spent Primer University that rigidly trying to ensure the scope is level and directly above the bore (#1) leads to far more shots where the scope is canted to gravity (#4 and 5) which is detrimental. It’s also been demonstrated that the incremental offset introduced by making the rifle comfortable to the shooter and the scope plumb to gravity is a nonissue (#6 and 7). Meaning the error is so small, in relation to the other vectors acting on the shot, that it is not to be counted.
4 and 5 -Bad
6 and 7 -Good
8 and 9 -That guy is shooting off an obstacle leave him alone.
2 and 3 -Just got that scope mounted at the LGS, is going on Snipershide later tonight to find out how to get his scope “right” (#1).
For the sake of clarity, I’m referencing your illustration by numbering the examples left to right, top to bottom, starting at 1, and ending at 9.
It has been observed by the faculty of Spent Primer University that rigidly trying to ensure the scope is level and directly above the bore (#1) leads to far more shots where the scope is canted to gravity (#4 and 5) which is detrimental. It’s also been demonstrated that the incremental offset introduced by making the rifle comfortable to the shooter and the scope plumb to gravity is a nonissue (#6 and 7). Meaning the error is so small, in relation to the other vectors acting on the shot, that it is not to be counted.
4 and 5 -Bad
6 and 7 -Good
8 and 9 -That guy is shooting off an obstacle leave him alone.
2 and 3 -Just got that scope mounted at the LGS, is going on Snipershide later tonight to find out how to get his scope “right” (#1).
1.5” of error at 1000y per the above example of 5* is <.05 of a mil. Is your wind call down to .2 of a mph in accuracy? Are you holding the reticle level to gravity with less than .1 degree of cant? Are you holding the rifle itself steadier than .05 of a mil? Are the impacts for your zero dead in the center or slightly left or right on average from the bullseye, because your scope only moves the reticle .36” per 1/10mil at 100y? If you say, “.2 mph accuracy of a wind call or a slightly left or right offset from my zero” is “good enough” or “it doesn’t matter,” then neither does 5* of rotation of the scope relative to the bore.
I get my rifle, I get my optic, I set up my rifle how I’m going to shoot it most often at longer distance, I move the scope front/rear to set the eye relief, and then I rotate the scope to level with gravity for my shooting position without worrying about how level the rifle is. I then try some other positions for how I’ll be using that rifle and may adjust the eye relief if necessary or otherwise tweak the orientation of the scope. Then I setup again how I’m going to shoot it most often at longer distance and make sure the eye relief is good and the reticle is level with gravity and I tighten it down.
Then when I get on the rifle to shoot it should settle into that natural position of where it’s comfortable for me to hold it which is where the reticle is level to gravity and which can be confirmed visually based on surroundings relative to the reticle through the scope. Then I pull the trigger.
You can set up the scope the way that you describe as well, but in the end, as I said, it doesn’t matter. My scope usually end up rotated 1-3* depending on the rifle/stock. At that point we’re talking about less than an inch error at 1000y, and the only way you’d see it, even at 5*, is if you did all those other things above perfectly. If you shoot with the reticle off level from gravity at long distance the error is much, much greater, so I choose to prioritize my shooting position that yields to naturally holding the rifle with the reticle level without needing to dick around with checking a bubble level.
yep, that will do it, won't it? I have a KMW Loggerhead adjustable comb kit on one of my guns and aside from height adjustment, what I love about it is that I can move the comb over to the right so I don't have to roll my head over the somewhat wide comb (ok, cheek piece) in order to get my eye behind the scope.
That lateral adjustment is a very handy feature that you don't see on too many rifles though its common on competitive shotguns.
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