Scope mounting

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Jerry G
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Scope mounting

Post by Jerry G »

I just came across a neat gadget to level a scope. It is called a Segway Reticle Lever.

I also got some instructions from a scope manufacture not to torque the scope rings over 15 in/lb.
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Re: Scope mounting

Post by Bigfoot »

Great tip Jerry. I just ordered one!

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Re: Scope mounting

Post by DavidABQ »

Hey Jerry, are you going to post a photo of it when it arrives?
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Re: Scope mounting

Post by Jerry G »

The picture is on the website.
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Re: Scope mounting

Post by OldRanger »

Yeah I have one of those. Problem is when my reticle is level my head isn't so I end up canting it a bit anyways. The product works great, but I do wish they had put a magnet on the top level too.
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Scope Leveling

Post by teetertotter »

I thought I'd inject:
My natural shouldering of rifle is canting and my scope is thus rotated in opposite direction for level. Everything lines up naturally for me, to the target.

I tried the perfect leveling of the rifle and then the scope. With practice, I'm sure I could have taught myself to shoulder the rifle in a level position.

I didn't start shooting until age 65 and I didn't feel like readjusting to shouldering the rifle. As mentioned, I did try with the so called, "Perfect Leveling," set-up.
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Jerry G
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Re: Scope mounting

Post by Jerry G »

If your scope isn't level with your rifle, your windage will be off as you shoot farther out. If you are good with that, don't bother to level the scope to the rifle. :-bd
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Re: Scope mounting

Post by Doodaddy »

Jerry G wrote:If your scope isn't level with your rifle, your windage will be off as you shoot farther out. If you are good with that, don't bother to level the scope to the rifle. :-bd
If the gun is always shot with the scope level with the ground rather than level with the rifle (in a rest, standing, propped up, always), there will be no windage issue no matter if the scope is perfectly aligned with the rifle or canted 45 degrees.

However if the scope is perfectly aligned with the rifle and your hold cants the entire rifle, you will absolutely have windage issues that are exacerbated over distance like you said. A small rotation out of alignment can really be exaggerated on some long shots. Since teetertotters hold cants the rifle, the compensation by canting the scope the opposite direction so that its alignment with the ground is proper, there is no windage issue.

The alignment of the scope with the rifle doesn't truly matter as long as you are always consistent with with scope alignment with the ground. On a benchrest gun it's the easiest to level the rest, level the target, mount the scope, align the reticles on the a corner of a square on the target, tighten the rings. Then each match, level the rest and level the target each time it's hung and there will never be an alignment issue. With silhouette considering we are shouldering the rifle and aren't exactly "stable", repeatability with scope alignment is nearly as important as the hold. A reasonable change in scope alignment can easily cause a miss at rams.
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Jerry G
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Re: Scope mounting

Post by Jerry G »

If your vertical x hair isn't aligned with the center of your bore your shot will be off in the horizontal axis. It is simple geometry. Try the 45 deg cant at 1,000 yards and get back to me. If your cant is up on the right your shot will go left. as you move your elevation x hair the dot will follow the vert x hair which is point toward the left and that is where the bullet strike will be.

Shooting bench rest you are not trying to hit the center of the target, you are shooting for group. Shooting a HP at 100 yards is not a test of your scope being slightly out of level.
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Re: Scope mounting

Post by Doodaddy »

Jerry G wrote:If your vertical x hair isn't aligned with the center of your bore your shot will be off in the horizontal axis. It is simple geometry. Try the 45 deg cant at 1,000 yards and get back to me. If your cant is up on the right your shot will go left. as you move your elevation x hair the dot will follow the vert x hair which is point toward the left and that is where the bullet strike will be.

Shooting bench rest you are not trying to hit the center of the target, you are shooting for group. Shooting a HP at 100 yards is not a test of your scope being slightly out of level.
First of all real rimfire benchrest does not shoot group. IR5050, ARA, PSL, BR50 (I doubt this BR50 even exists in today's time. ARA and PSL dominates.) All for score. All the center of a bull. Usually 25 bulls on a card. I've shot them all. I still have the targets. One is even framed in my office. Some centerfire does shoot group. Group shooting isn't exciting to me. All of this is entirely beside the
point.

What exactly are you implying a shooter is to do? Is your hold perfectly aligned with trajectory? Not unless by some freak chance. Do you hold it naturally while incuring a cant with the scope's reticle in relation to trajectory or do you compensate with your physical body to align the scope's reticle with the horizon?

Either scenario you lose. A compromise in POI/POA relations or a compromise in physical stability. Either can show up on a score card. One could argue that the hold could be learned and stability be restored over time, but that's relative to the shooter. I'd rather align the scope's reticles with trajectory and compensate windage wise if needed across the animal distances. I haven't come across a need to adjust windage in our silhouette distances though that could be related to either the change in distance being too little or my starting point with zero. I usually leave zero the rifle by scope ring shims (Burris signature zees) at the distance that is the exact middle between chickens and rams (70 meters) before I make any turret adjustments to keep all of the adjustments of my scope as close to the center as possible. This could create a situation where the windage error is negligible entirely for our shooting discipline as any alignment issues are on both sides of my zero and not allowed to be exaggerated enough to be a problem.

I'm not arguing that a scope cant won't introduce windage issues. It's not debatable. I read up on that many moons ago and to figure out why I was having windage issues when standing shooting, but not in my rest. I cant the rifle when standing, but don't in the bags. I'm arguing that I don't have windage error within the silhouette game with my scope mounting.
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Jerry G
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Re: Scope mounting

Post by Jerry G »

If you zero at 40 and come up 9 min for 100 then.................... with a 45deg cant. your windage will be off by 6.36 minutes. I do realize 45 is an extreme cant but the same math applies for any degree of cant. That would make 1 degree worth 0.141 minute.

a=b tan A where
A is the angle of cant
a= amount of windage in minutes
b= minutes of change from zero to new sight setting for target

If your cant is only a couple degrees, the error will be covered by your group size. The more cant, the greater the error. It is simple trig most of us old farts learned in high school. I am retired and haven't used trig for 10+ years so someone may want to check me on that. I know you are an engineer Dave, check my logic and math.
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Re: Scope mounting

Post by thauglor »

But what Doodaddy is saying is that his scope is perfecrly straight while the rifle is canted. Yes the scope is not over the bore, but his scope elevation will only produce an elevation on target, no windage since his scope is straight up and down and not canted relative to the ground. That will insure a tiny bit of windage at longer distances since scope is offset compared to the bore, but at these distances it is probably negligible.
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Re: Scope mounting

Post by Doodaddy »

Jerry G wrote:If you zero at 40 and come up 9 min for 100 then.................... with a 45deg cant. your windage will be off by 6.36 minutes. I do realize 45 is an extreme cant but the same math applies for any degree of cant. That would make 1 degree worth 0.141 minute.

a=b tan A where
A is the angle of cant
a= amount of windage in minutes
b= minutes of change from zero to new sight setting for target

If your cant is only a couple degrees, the error will be covered by your group size. The more cant, the greater the error. It is simple trig most of us old farts learned in high school. I am retired and haven't used trig for 10+ years so someone may want to check me on that. I know you are an engineer Dave, check my logic and math.
The math seems fine, but isn't related to my question at all. Did you adjust your physical hold or is your rifle canted when fired?
thauglor wrote:But what Doodaddy is saying is that his scope is perfecrly straight while the rifle is canted. Yes the scope is not over the bore, but his scope elevation will only produce an elevation on target, no windage since his scope is straight up and down and not canted relative to the ground. That will insure a tiny bit of windage at longer distances since scope is offset compared to the bore, but at these distances it is probably negligible.
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Jerry G
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Re: Scope mounting

Post by Jerry G »

A picture may help.
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Re: Scope mounting

Post by OldRanger »

Jerrys got it right. The big problem is the slight angle that the bore is at to aim at the place the dot is looking. I had to adjust my hold for high power as with the scope canted the horizontal changed something like 20 inches at 500 meters with a 200m zero. I could have just adjusted for it, but better to just stay true.

Now for smallbore my miniscule cant for my comfort and hold is less than an inch at 100m so I just accept that and hold accordingly.
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