A new finding in achieving accuracy.

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Emu

Emu

Member
Jan 15, 2020
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Queretaro, Mexico
This might have been obvious for many of you, but I got amazed by the finding I made today, after having shooting as my main hobbie for 55 years.

"If you do not have a bubble level on your scope you may not notice you are loosing the correct angle in which you hold your rifle and, then, you can easily hit left or right, no matter the distance at which your target is."


 
Yes, I just noticed this too. I had been sighting and shooting my gun without a bubble level on my scope for the longest time and shoot at an angle that is natural to me or what I thought the cross hair is straight to me. I bought a bubble scope because I wanted to make sure I am shooting accurately straight. Low and behold the bubble level is telling me I had been holding my gun at an angle this whole time. The weird thing is, the correct level position is just so unnatural to me and the cross hair looks angled and unnatural to me. I mounted the scope and bubble level numerous times to ensure I mounted correctly too. I guess I have to trust the instruments and adjust to my shooting positions.
 
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Yes, I just noticed this too. I had been sighting and shooting my gun without a bubble level on my scope for the longest time and shoot at an angle that is natural to me or what I thought the cross hair is straight to me. I bought a bubble scope because I wanted to make sure I am shooting accurately straight. Low and behold the bubble level is telling me I had been holding my gun at an angle this whole time. The weird thing is, the correct level position is just so unnatural to me and the cross hair looks angled and unnatural to me. I mounted the scope and bubble level numerous times to ensure I mounted correctly too. I guess I have to trust the instruments and adjust to my shooting positions.
Click to expand...

You can probably get an adjustable butt plate so that make the hold feel " normal" to you, even with the scope and bubble level mounted true with the bore's centerline.
 
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So

If consistency is what accuracy is all about, then a - say 5 degree cant, consistently held might be workable if A distance is zeroed in. Predictably, but not established in my experimentation, corrections on windage and hold over would both be needed for distant or proximal targets, even though say at a fixed distance you might get consistency. So better to get the cant out of the equation and Do it right. Has someone proven this for us - so i don't have to go out and prove it in the dark?
 
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Has someone proven this for us - so i don't have to go out and prove it in the dark?
Click to expand...

Is cant error an elaborate hoax perpetrated by ballisticians, long-range shooters, and an evil worldwide network of spirit level and aluminum extrusion manufacturers?

Probably.

Or...perhaps we can take a scoped rifle and aim at at target and shoot, rotate it by 45 degrees clockwise and take another shot, and continue until we have completed a full rotation and we will have a target that looks like this:



...where the holes form a circle with a radius equal to the amount of pellet drop at whatever distance we are shooting.
 
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So

If consistency is what accuracy is all about, then a - say 5 degree cant, consistently held might be workable if A distance is zeroed in. Predictably, but not established in my experimentation, corrections on windage and hold over would both be needed for distant or proximal targets, even though say at a fixed distance you might get consistency. So better to get the cant out of the equation and Do it right. Has someone proven this for us - so i don't have to go out and prove it in the dark?
Click to expand...

Yep I leave my scope a little left at close range to be dead in @ 45yrds.The degree left is not enough to cause a miss (1/4") so no scope level needed for my hunting rig.
 
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Emu,

Need to make sure the scope is level and centered with respect to the bore as well. This is a guide to (scope and/or gun) cant related errors with respect to unexpected POI for distances closer and farther than the distance your scope is zeroed:

Screenshot_2019-07-04-23-06-44.1640528001.png

 
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Emu,

Need to make sure the scope is level and centered with respect to the bore as well. This is a guide to (scope and/or gun) cant related errors with respect to unexpected POI for distances closer and farther than the distance your scope is zeroed:

Screenshot_2019-07-04-23-06-44.1640528001.png
//www.w3.org/2000/svg%22%20viewBox=%220%200%20210%20140%22%3E%3C/svg%3E
Click to expand...

Thanks a lot.

This forum is an asset for our hobbie!
 
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If the Bubble says your level and the scope looks canted why not rotate the scope to be true to your vision? The cant issue is in the mechanics of the rifle and your view through the scope. Make the scope true level with the bubble. You may not have had the scope true to the gun because of your hold it looked right until the bubble proved you wrong.
 
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Level the gun, level the scope, then double check before tightening anything. The, after tightening, double check again.

You can accomplish much of the same by using leveling wedges in a jig. Amazon.com : TXTactical Scope Leveling Tool, Scope Leveler, Scope Leveling Wedge : Sports & Outdoors

These work pretty well by leveling against the gun itself. Ensures the relationship between gun and scope is consistent. Or if you have a 3d printer, you can print a set for 25 cents: Scope Leveling Jig by 1Eye - Thingiverse

I printed a set and oh, how much simpler it is to level a scope now!
 
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On all my rifles in order to shoot straight, I use on bubble level on the scope rail and another seated on the up/don't turret. The one on the rail should be centered and the one on the turret should be a little bit fall to the left.

Then the bubble level locktited to another scope ring ( the one that will be kept in the scope) should be centered with the bubble level on top of the up/down turret.

Once done that I shot perfectly centered at 200 yards and at 20 yards. The execese I made yesterday surprised me A LOT !!!
 
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Please note that using wedges or bubble levels on the scope turrets makes a variety of assumptions about the perfectness of machining and assembly features that may or may not be true. Most of the time the result will be better than just eyeballing it but if you want to be sure the scope is installed correctly, use a laser boresighter or a mirror to center the vertical bar of the reticle with the bore.

Everyone has a mirror but perhaps not a laser boresighter so let's go over the mirror method for installing a scope and then how to install a level. First let's establish that the requirements to eliminate cant error are two-fold:

1. Align the scope's reticle with the rifle's barrel.
2. Hold the reticle level when shooting.

Item 1 deals with scope cant…i.e. mounting the scope incorrectly.

Item 2 deals with gun cant…i.e. holding the gun incorrectly.

To correctly align the scope to the barrel, set up a mirror at a distance of, say, 5 yards and set your AO to 10 yards. Look through the scope at your reflection in the mirror. Twist the scope in the mounts until the vertical bar of the reticle simultaneously bisects both the muzzle and objective bell. Then lock it down. At this point you have eliminated scope cant (item 1). If it's hard to see your muzzle, add a little dot of White Out or take a dot from a hole punch and tape it to the muzzle with clear tape.

Now to eliminate rifle cant, install and use a level. View a known good plumb line (e.g. hanging string) through the scope and orient the rifle so it precisely aligns to it. Now affix your level so it shows level. From now on when you're shooting, hold the rifle so it shows level and you can be sure you've eliminated both potential sources of cant error.

By the way, don't buy a level that attaches to the scope rail. There is no guarantee it will show level. Instead, get one that attaches to the scope tube so you can rotate it and lock it down where it shows proper level with a plumb line.
 
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Level the gun, level the scope, then double check before tightening anything. The, after tightening, double check again.

You can accomplish much of the same by using leveling wedges in a jig. Amazon.com : TXTactical Scope Leveling Tool, Scope Leveler, Scope Leveling Wedge : Sports & Outdoors

These work pretty well by leveling against the gun itself. Ensures the relationship between gun and scope is consistent. Or if you have a 3d printer, you can print a set for 25 cents: Scope Leveling Jig by 1Eye - Thingiverse

I printed a set and oh, how much simpler it is to level a scope now!
Click to expand...

I use a similar devise to this but different brand to level my scope. Really easy to use. Now my question is, how to know for sure the crosshair is perpendicular the flat bottom of the scope, or the the wedge is machined to the right specs. I am doing more research now, it appears using a plumb line to double check the vertical line of the croshair also works.
 
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One problem I've come across is the cheaper levels are often different so I don't know which one I can trust. I suppose that's my fault for not spending enough $$ to get precision levels.

Another problem is sometimes there's no flat spot on the rifle to put the level on. Or if there is a flat spot I can't fit a level under the scope.

Another besides that "when looking down at a level which is sitting on top of a turret" is if I have the level at a slightly different direction, meaning that if using the clock example and the level is in the12:30/6:30 position the bubble is not the same at the 11:30/5:30 position.

At this point in my life, and after achieving plenty of high finishes, or winning, using all kinds of rifles and scopes, in a wide range of types of matches, in which I'm pretty sure didn't have perfectly level scopes on them, I am just not worried about using levels anymore. The best example I can think of is using holdovers and holdoffs in a long range centerfire steel series to win it two years in row. As well as winning one ELR match. Sometimes I used a level but most of the time I didn't.

In fact I prefer the look of the crosshair appearing straight when I know its not leveled correctly with the rifle, rather than truly level or close to it in which gives the appearance through the scope of the crosshairs clocked counter clockwise slightly. This probably worked out well for me because when shooting I hate it when the crosshairs look like they aren't level so I always strive to make them appear proper to me.

I know that my words here drive people nuts who look at the math and consequences of not having the scope and rifle perfectly level but I just haven't seen poor results in actual situations where level and plum being slightly off made enough difference to matter. At the same time if these were way off then yes that could be a problem.
 
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I like the mirror idea and am going to give it a try to see how far off my scope levels are I normally level the gun and then level the scope off the turrets and double check the level of the gun and scope level match I've also noticed according to the levels I naturally hold the gun canted like others have stated that only flat place to put a level on the gun is usually on the scope base so I will check how close my levels are in the mirror Thanks for the tip

Ps: mirror also works good to optically center the cross hairs on a scope that was removed from a different gun just hold it up close to the mirror and adjust cross hairs to line up 
 
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