Canting

Level the scope with the barrel,vertical crosshair should be dead center going down the barrel, it’s your hold that cants the scope view, I had this issue long time ago and just had to readjust how I shouldered the rifle and adjust my cheek position on the stock a bit.

So there are two functions to leveling a gun (any gun). The first is obvious: consistency. If you cant your gun a different amount every time, you'll spray pellets laterally all over the place. 


There is a second more subtle element to it though. The "vertical" of your gun has nothing to do with the stock or anything like that, if it were just about consistent angular hold you could technically flip your gun on its side or at 45 degrees and call that "level" as long as you held it consistently. You can't do that though, and the reason is your barrel. You need your barrel to be directly below the crosshairs of your scope, although most shooters just settle for centered on their scope rings. Why? Because you input a height-over-bore of your scope in your ballistic calculator. That way the offset between your optic and your barrel is on just one axis. If you don't have this, you'll zero at one range and everything will be fine, but as you shoot at nearer or further targets your point of impact will start to wander left-right relative to the vertical axis of your crosshairs. 

At this point I should note that many scope rings are not made to particularly high quality. Want proof? Put the pair of them next to each other on your rail but with one flipped. Note how the tube cuts don't match up perfectly? Thats your offset from centered. If you bought a good gun, and it was designed by someone with their head screwed on straight, at least your scope rail should be centered on your barrel.  



As far as "feeling level" when shouldering, don't worry yourself about it. Install a level on your scope (I'm partial to the Accuracy 1st ceramic ball levels, in part because they take trits so run at night, but a boring old scope mounted bubble level will do) and true the whole system up very carefully. Then just run based on the bubble level on your scope, and ignore the "feel" of the rifle/terrain/etc. Those perceptions serve you well for not falling over, but can horribly mislead you when it comes to precision shooting. Also I try to avoid the rail mounted levels for two reasons: 1) I've gotten poor consistency from the ones I've seen and 2) the angle of your rail isn't necessarily the vertical of your gun. 

I hope all that made sense and I didn't have any bad typos or errors in there. 

My 2c. 

STO, I think you are hitting on a key point here which is that there is nothing about the stock or the action that can be reliably used as a reference level surface…neither for the purpose of installing the scope nor for the purpose of holding the rifle level. It assumes everything is machined absolutely perfectly and the scope rings are perfectly centered over the rail and the barrel is perfectly straight…but that’s a lot of things that have to be perfect and reality often has other plans.

Fundamentally there are just two conditions that need to be satisfied to eliminate cant error:
1. That the scope’s reticle is properly oriented to the barrel. This step eliminates scope cant.
2. That the gun is held level. This step eliminates gun cant.

To satisfy #1, there are commercial jigs you can buy but there is an easy way to do it that requires no special tools. What you do is set up a mirror at a distance of 5 yards and set your AO to 10 yards. Then look through the scope at your reflection. Rotate the scope until the vertical bar of the reticle bisects both the muzzle and objective bell. Put a small white sticker or little dab of White Out on the muzzle to make it easier to see. Now lock down the scope in the rings, taking care to prevent it from rotating when you tighten the screws. Check your reflection one last time to make sure. At this point your scope is properly oriented and scope cant is eliminated.

Now turn your attention to preventing gun cant. The way you accomplish that is to view a known good plumb line through your scope (a hanging string, for example). Now orient the gun so the reticle aligns to your plumb line, and affix your spirit level to the scope tube so it shows level. From now on, trust the level when you’re holding the gun. Trust the level because your reticle is aligned to the barrel, and the reticle is being held precisely in the line of the force of gravity.

By the way, when you use this method, there is absolutely no need for the scope to be perfectly centered over the rail. Doesn’t matter if it’s 3/8” rings on an 11mm rail or vice versa. So if you are looking at pricey rings that promise to solve this non problem, keep your money in your pocket.

That is a pretty cool trick, nervous. I'm going to check mine, which I think is right, and see if it is aligned.

Thanks for the tip.



Crusher

Generally speaking a barrel is round and doesn't know up from down or left from right its the scope or sight that's necessary to be level. Some shooters cant the rifle to shoot it while standing bringing the scope to their head with the rifle canted. As long as the scope is level the bullet will hit the same poi. David Tubb is one such shooter.

STO, I think you are hitting on a key point here which is that there is nothing about the stock or the action that can be reliably used as a reference level surface…neither for the purpose of installing the scope nor for the purpose of holding the rifle level. It assumes everything is machined absolutely perfectly and the scope rings are perfectly centered over the rail and the barrel is perfectly straight…but that’s a lot of things that have to be perfect and reality often has other plans.

Fundamentally there are just two conditions that need to be satisfied to eliminate cant error:
1. That the scope’s reticle is properly oriented to the barrel. This step eliminates scope cant.
2. That the gun is held level. This step eliminates gun cant.

To satisfy #1, there are commercial jigs you can buy but there is an easy way to do it that requires no special tools. What you do is set up a mirror at a distance of 5 yards and set your AO to 10 yards. Then look through the scope at your reflection. Rotate the scope until the vertical bar of the reticle bisects both the muzzle and objective bell. Put a small white sticker or little dab of White Out on the muzzle to make it easier to see. Now lock down the scope in the rings, taking care to prevent it from rotating when you tighten the screws. Check your reflection one last time to make sure. At this point your scope is properly oriented and scope cant is eliminated.

Now turn your attention to preventing gun cant. The way you accomplish that is to view a known good plumb line through your scope (a hanging string, for example). Now orient the gun so the reticle aligns to your plumb line, and affix your spirit level to the scope tube so it shows level. From now on, trust the level when you’re holding the gun. Trust the level because your reticle is aligned to the barrel, and the reticle is being held precisely in the line of the force of gravity.

Click to expand...

You just blew my mind. Here I've been using an incredibly convoluted string of careful measurements and tests and checks to achieve this, and this does it potentially effortlessly. That is amazing. 

Mod 3 edit: removed 4 letter F word. Don't let it happen again!

" why does it feel not level when holding/shouldering it? "

from Mic the Fuzzy Limey " doesn't fit you".

We all can ( or try ) to adapt to anything. A winchester level style rig inst as easy to use -scoped- as something that will give you check weld.

I've been lucky enough to have a couple of "Custom" stocks, not after market stocks but tailor fit . Close your eyes , shoulder it and spot on the 10 ring level & square everytime.

You will see many shooters using custom offset ( some extreme) butt pads and such as well as other tricks just so the rifle fit's them - not one size fits all.

Chop cut grind add bondo , anything that makes it fit & feel natural ( w/eyes closed ) and puts you on target correct is a worthwhile mod. Unless your rigs are just for looking good.



John

Good thing I didn't chime in, I would have guessed and disagreed with nervoustrig on the grounds that 11mm is wider than 3/8", converted to decimals aprrox .432 vs .375. I didn't figure on the angles' effect. All this time I have been doing it wrong, though I have never had an issue. I guess it is true, " an old dog can learn a new trick"

Cheers

Yeah it's confusing. The discrepancy is related to how they are dimensioned. An 11mm rail is dimensioned to the widest part of the dovetail whereas a 3/8" rail is dimensioned to the narrowest part...which is how 3/8" (0.375") is paradoxically larger than 11mm (0.433").

Where's the "snek"'s input on this???

No step on snek 

https://www.airgunnation.com/topic/scope-reticle/#post-339336

nervoustrig, You are a rock star. Many thanks.