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Annoying Scope Cant "Corrected" finally

moajoe

Some background: Bought a Savage Model 12F off of gunbroker to get into the F-Open game and stay within my budget. Was advertised as a 6mm BR, when I went to the gun shop to pick it up it had a 6.5-.284 barrel on it. Came in original box with all documentation. It also had a 20 MOA rail installed. Switched out the barrel for a new 6 Dasher by Brux.

Purchased a new Nightforce 12-42 x 56 BR scope and nightforce rings. Put everything together and load up some lapua brass for fireforming. When I look through the scope the left side is lower than the right side. While at the range I get out my little scope level and re-adjust the scope in the rings.

I now purchase a SEB Neo rest so now I can do a better job of leveling the rifle. Rifle levels out and the top turret of the scope is way out of level. Adjust the scope so the turret is level and the cross hairs are canted. This is driving me nuts.

Go home and take the scope off to level the rifle. Pull the bolt and place my small level right behind the action opening and level the rifle in the rest. Put another spirit level perpendicular to the MOA rail and it is way out. So now the rifle is level but the rail is not. Find the smallest torx driver I have to undo the screws holding the rail to the action. Evidently one side of the rail is a hair shorter than the other side. Crap.

Until I can get a new rail I just shimmed the rail up to level and remounted the scope. Verified rife is level now the turret is level. Did the shine a bright flashlight into the objective end the of scope (saw this method in a thread on this site) to project the cross hairs onto the wall in my "gun room" and verified they were also level.

I am off tomorrow for the Memorial day weekend and will be back at the range doing some load development for an upcoming 1,000 yard match. Hoping this all works out well.
 
The scope base being level is largely irrelevant. I use a tool that may be a collectors item. They may no longer be made. Brownells sold it for decades. It is called a vertical reticle instrument. http://www.firearmsinsider.tv/gun-gear-reviews/exd-engineering-vertical-reticle-instrument
Using it allows you to put the center of the scope on a vertical line with the center of the barrel. Once you have the rifle in that position (done by referencing the tool's spirit level) you can roll the scope so that the vertical cross hair is parallel with a plumb line, or if you are less fussy, use a level on the top of your turret. I have done the latter many times and never had a problem. Understand, the position of the scope and barrel may be correct relative to each other, and the bottom of a flat bottomed stock can be off, but that by itself is not a problem except that you can't use it as a reference for setting up at the range. Personally, I use a trick that I picked up from an experienced small bore shooter that I saw using a torpedo level to hang his target after placing his target frame down range. Doing it that way gives you convenient vertical and horizontal references in your scope while shooting. Eliminating the need for a scope level, at least when shooting at the range.
 
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Or, it's fortunate that reticle cant means nothing at all -> if you dial elevation & hold off for wind & mirage. You might be using a simple dot POA. In this case, elevation adjustment needs to be plumb(not level and not with Earth, but plumb with local center of gravity).

Many times I've read complaints of scope reticles being turned in manufacture. They're not square with references folks use(like a turret top). Makes me glad I'm a dialer. I can plumb a scope's elevation adjustment, cinch down a 'ScopLevel' on that scope, and move it forever from gun to gun to gun and never have to mess with that attribute again. I don't care about canting with rings, bases, action mounting, stock & bedding, or where a barrel's pointing. Doesn't matter to me.
When I dial up XXmoa, the POA does so in a plumb manner from my zero. The gun itself could be sideways and it doesn't matter.
Now if I want that plumb adjustment from a zero that has the gun square to something (like a level bench rest), that's just what I spin the scope to in it's Rings. I preferred 7degs gun cant from level Harris bipod with my T2k.
 
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Mike, how would one find this plumb to local center of gravity? Also, how is plumb to local center of gravity different than level to the Earth?
Thanks

Reality is, the reticle doesn't need to be level or plumb so long as its the same every time.
 
Unless established so, Plumb is not level.
And center of gravity is usually not truly straight down from just any topography or item resting on the Earth's surface.
When you hang a weight from a sting, it hangs on an axis that gravity forces it to. There is no particular reason for a target backer you hung that string from, or the ground, or your shooting bench, or gun, to be level/square to this axis. They probably are not.
No matter, a bullet will fall on the axis the string is showing.

I only refer to 'local' gravity because it is slightly different, nearly everywhere. Technically, your mountain gravity is different than my beach gravity, and between them, 'down' or 'center' can be different directions.
 
My goodness! I think that most of the world defines level as perpendicular to plumb. I you hang a target that has has adjacent sides at right angles, you can either use a vertical side to set the target by, in which case the horizontal sides will be level, or level the a horizontal side (with a level) and accomplish the same thing. Why all the complication? Level vials work off of gravity too.
 
If the horizontal cross hair is not in the same relation to true level, or the vertical to true plumb, (whichever your preferred reference is) for all shots in a group, that group will be larger than if they were. Not all stocks have wide flat forends, and I like to shoot groups that are as small as I can make them, so I do bother myself about shot to shot consistency of rifles' cant. or lack thereof. That is why I post my targets so that their tops are level. It is the handiest reference for me.
 
Alex Wheeler said:
Mike, how would one find this plumb to local center of gravity? Also, how is plumb to local center of gravity different than level to the Earth?
Thanks

Reality is, the reticle doesn't need to be level or plumb so long as its the same every time.
Click to expand...

Alex,
If I understand you correctly. The scope could be slightly tilted to the left because of the uneven base rail, I could just rotate the scope to level it and that would be good? As long as it tracks true with elevation and windage? Would the scope no longer be over the bore axis but slightly to the left of center? I ask because I am fairly new to all of this.
 
moajoe said:
Alex,
If I understand you correctly. The scope could be slightly tilted to the left because of the uneven base rail, I could just rotate the scope to level it and that would be good? As long as it tracks true with elevation and windage? Would the scope no longer be over the bore axis but slightly to the left of center? I ask because I am fairly new to all of this.
Click to expand...
Rotate the scope until it looks level to your eye when you hold the rifle. You can hang a plumb bob, line up your cross hair and install a level on the tube. My eye can do a much better job just looking at the reticle and knowing its level to the world than looking at a level bubble. But thats up to you. Even if you cant the scope, so long as its canted the same everytime you will be ok. Look up a tall target test. This will help you figure out if the reticle is level to the workings of the scope. For dialing you really want your level to be installed perpendicular to the travel of the erector assembly.
 
https://forum.snipershide.com/blogs...f-gravity-and-your-rifle-to-your-natural-hold

Rifle%20cant%20with%20scope%20level%20explanation%202.005.jpg
 
spife7980 said:
https://forum.snipershide.com/blogs...f-gravity-and-your-rifle-to-your-natural-hold

Rifle%20cant%20with%20scope%20level%20explanation%202.005.jpg
Click to expand...
I don't believe their is a natural cant. Either you can't the gun or you don't. I believe most BR guys level their scopes and rigs. If you don't, when you put on elevation it will not go straight. This is also effected by how high the scope is. BR guys tend to mount their scopes higher and it will effect the impact even more. So there is no set of numbers this will work out to, being dependent on scope height. Must be why I don't go to Snipershide. Matt
 
dkhunt14 said:
I don't believe their is a natural cant. Either you can't the gun or you don't. I believe most BR guys level their scopes and rigs. If you don't, when you put on elevation it will not go straight. This is also effected by how high the scope is. BR guys tend to mount their scopes higher and it will effect the impact even more. So there is no set of numbers this will work out to, being dependent on scope height. Must be why I don't go to Snipershide. Matt
Click to expand...

I know when I shoulder my rifles they all tend to want to tilt to the left a bit. Thats just how my shoulder anatomy is built I suppose. In that event it is better to have the reticle aligned with gravity and allow me to not muscle the rifle when I shoot rather than having the system all in perfect alignment to one another but then muscling it off of level to be comfortable. Sure with a 40 pound front rest on a 500 pound cement bench and an adjustable recoil pad to make your natural hold vertical theres not much reason to have anything not perfect. But get outside of that where things arent always exactly perfect and things can change. I feel like you didnt actually read what the article was saying. It boils down to leveling the reticle to gravity will have less of an influence than a perfectly level system getting canted away from gravity by the shooter.
 
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