Scope Levelling?

Shooting Supplies : Ammo - Reloading - Firearms - Optics - Accessories
4

4535jacks

Well-Known Member
I have just mounted a new scope to a hmr and mounted it so when I mount the rifle in my shoulder the recticle is vertical. However it looks like the recticle is not level with the action which makes sense since my head has a slight cant.

Is it crucial to get the scope recticle perfectly level with the action or it is more important to mount the scope so the recticle is level when in the shoulder accepting that the rifle will be slightly canted to one side?

Thanks in advance,

Gary
 
Yes it is.

I mount scopes by first setting up the rifle straight. Put it in a gun vice, a spirit level across the lower half of the mounts and clamp it up when square. Then put the scope on, spirit level across the top of the turrets and clamp that up.

If it's not square when you make an adjustment to crosshairs rather that go straight up it will go up and left a bit or up and right a bit.
 
NigelM said:
Yes it is.

I mount scopes by first setting up the rifle straight. Put it in a gun vice, a spirit level across the lower half of the mounts and clamp it up when square. Then put the scope on, spirit level across the top of the turrets and clamp that up.

If it's not square when you make an adjustment to crosshairs rather that go straight up it will go up and left a bit or up and right a bit.
Click to expand...

+1
you can by a couple of manetic levels off eBay or Wheeler no a couple of purpose made ones.
Bryn
 
Now if ALL you ever do is shoot deer within a small bracket where your target is between seventy-five and one hundred and fifty yards and your cant is always consistent it won't make much difference. Yes you shot string will line up "on the cock" but will give a point of impact near enough to give a killing placement of the bullet.

Or in another very limited circumstance of if all you ever shoot is from your back doorstep at crows sitting on a a solitary and single fence post that you have erected for the purpose of baiting crows to sit on it so as to shoot them. And never anything but at that crow on that post. As the only factor to compensate for will be mere lateral correction for crosswind by aiming slightly left or slightly right.

But remember that no matter of how little or how much you cant your rifle and regardless of how consistent or inconsistent that cant that YOU CANNOT CHANGE THE LAWS OF GRAVITY.

ELSEWISE THIS:

You are trying to correct imperfect gun mounting (that is how you hold your rifle) by turning the axis of your 'scope. Which unless you have a physical condition that causes that is a case of trying to make two wrongs equal one right.

In effect instead of the having a clock showing midnight in that BOTH 'scope and rifle are like the clock hands pointing to 12 o'clock you are, in an extreme case, at five past midnight. Where the 'scope is like the hour hand pointing at 12 o'clock but the rifle is canted so that it is at five past the hour. In which case your shot string won't be perpendicular but at 30 degrees to the that.

But at longer ranges it won't be. As the longer the range the further to the right and away from the perpendicular line described by your reticule will be the point of impact of your shots. So you won't be able to "hold over". And you will have to alter both elevation AND windage on your 'scope. That's why a common test for 'scope alignment if to fire three shots then dial in some elevation and fire another three shots. If correctly aligned the second group will be directly above the first group.

So yes other than the limited circumstance as above it is important to have both 'scope and rifle aligned at midnight and not one a twelve o'clock and the other at five past twelve. And correct your gun mounting.

It is why shot gun instructors always say don't correct poor gun mounting in a physically "normal" shooter by bad gun fitting but correct it by teaching correct gun mounting technique. If OTOH the imperfect gun mount is caused by a physical handicap or abnormality then yes, you would alter the gun fit so as to bring the alignment of the gun perpendicular.

So EITHER hold the rifle correctly with perhaps the aid of a bolt on 'scope level bubble accessory like the bubble on a spirit level that comes mounted to an supplementary 'scope ring (as others have advised) or if the cant is caused by a physical handicap or abnormality have the rifle stock altered to take account of that. To restore the rife to the true perpendicular. An offset comb perhaps or if the other way an increased sized comb.
 
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NigelM said:
Yes it is.

.....If it's not square when you make an adjustment to crosshairs rather that go straight up it will go up and left a bit or up and right a bit.
Click to expand...

Not true:

If the scope is canted to the action but is vertical when you shoot (because you shoot with a canted rifle) then any adjustment will still be in the vertical plane. The exception to this is if you try to adjust from shots not fired from a canted position.

My stalking and CF target rifles have the scopes vertical to the action, but my SB target rifle has a canted scope as it's only ever fired from shoulder unsupported and it's a more natural position for me.

I use a couple of cheep spirit level key rings off of ebay. One on the top of the reciever and the other on top of the scope turret.
 
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I use a Tier One scope leveler. Simple but effective. Only downside is if you have high mounts you need to put something under it to raise it up. I just bought a short length of 5mm aluminium flat bar off Evilbay to put underneath it.



Ian
 
Tier 1's with the build in levels are good. You can yse a normal level across the mounts as has already been said though. Set up so that the bubble is centred, fit the scope and plop one of those little round spirit levels atop the elevation turret, adjust until centred and pinch up bolts. Next, to test, set up a vertical stake or scope to a vertical wall some distance away (at least 25 to 50 yards), set the rifle up level and check through crosshairs that the vertical crosshair aligns with the vertical wall edge or stake. Some of these little cheap bubble levels aren't especially accurate so worth checking. You can also use a simple plumb bob attached to the top of the butt stock and alter the rifle until it bisects the exact centre of the buttplate as a check that the rifle is vertical.

Shooting with a canted rifle isn't a great idea as unless you use the exact same cant angle each time, you'll never be quite sure where your POI will end up. How many of us can be sure that a cant is exact every time? Rifle fit is often ignored, where shotgun fit isn't, yet it is just as important.
 
Having placed your rifle in a gun rest/vise and made sure its level then mount the scope and plumb the vertical hair with the use of a plumb bob hanging from the ceiling if all else fails.
 
Klenchblaize said:
Spot on. I've had two (2) Burris compact 4 - 12 power scopes where the elevation turret was at circa ten-o-clock when crosshairs aligned with action!

K
Click to expand...

Agreed, I set the rifle up on bipod and rear bag and adjust with spirit level until perfectly on the horizontal plane. I then mount the scope and line up the vertical crosshair with a piece of dark coloured string that I hang from the wall in plumb line style.
 
flying felix said:
Not true:

If the scope is canted to the action but is vertical when you shoot (because you shoot with a canted rifle) then any adjustment will still be in the vertical plane. The exception to this is if you try to adjust from shots not fired from a canted position.

My stalking and CF target rifles have the scopes vertical to the action, but my SB target rifle has a canted scope as it's only ever fired from shoulder unsupported and it's a more natural position for me.

I use a couple of cheep spirit level key rings off of ebay. One on the top of the reciever and the other on top of the scope turret.
Click to expand...

Now you're splitting hairs!
 
Just done it with mates rifle, set up in vice/rifle holder and put level across bottom half of bases, try both as I bet they will be different. If I am very picky I have a piece of 1/4 plate glass which I place on the bottom halves and it gives an idea which one is out the most.

With rifle level align scope reticule to plumb line hanging down the garden.

Also in my case with Burris signature rings and inserts I bore sight at 25 yds and align scope using inserts proves to be quite a good method.

Please note depending on the manufacturer the reticule may be up to 10 degrees out of true, so putting level on top cap may be an error.

I have rail levels on some of my weapons and if you shoot the box keeping the bubble at the same place you will also be able to establish if the scope is truly vertical.

Please note, when you set up the action level across the bottom bases look at your rail level as it probably wont read level however note where the bubble rests and hats where the action is level.

As previously stated cant not normally an issue but will be when shooting on a diagonal up or down a slope.

D
 
ChesterP said:
......Shooting with a canted rifle isn't a great idea as unless you use the exact same cant angle each time, you'll never be quite sure where your POI will end up. How many of us can be sure that a cant is exact every time? Rifle fit is often ignored, where shotgun fit isn't, yet it is just as important.
Click to expand...

And the same is applied with a non canted scope.............without a spirit level permanently fitted to a rifle you can't be sure its vertical.
 
Now if you really really want to do it once and do it right take the action and barrel out of the stock and use the bottom of the action as your 0 degree line. But as others say is that truly horizontal. I use the other method.

Take the bolt out. Put your eye a bit back from the 'scope and adjust the 'scope by turning it until the vertical reticule aligns with the visible bit of the sear that comes through your boltway.

Or on any Mauser if not as above put the bolt in, "fire" it and adjust the 'scope until the vertical reticule aligns with the visible back end part of the firing pin where it comes out through the cocking piece of the bolt.
 
A few more cheap and easy ways to align and verify that the scope is square with the action:

1. If the rings are joined horizontally, stick a still playing card in each side, and check the horizontal crosshair for alignment with that halfway mark on the rings.

2. Compare it to the vertical divide on rings like Warne and Nikon, the same way. Stick a placing card in the gap to help.

3. To see the crosshairs better, remove the bolt and look backwards through the scope

4. This brings me to another method:
Snug up the scope so it will not slide, but you can turn it to align it.
Put a piece of bright masking tape, like 3M painter's tape, along the butt pad, down the center of the screws.
Better yet, tape a piece of paper to the butt so the edge is exactly down the center of the pad.
Stand the rifle up on the floor and look down through the objective lense.
Turn the scope until the vertical crosshair aligns with the edge of the paper.
Tighten one screw.
Check again, tighten another screw.
Then put the rifle in its cradle and tighten the other screws.

5. Mount the rifle naturally, offhand, and aim at a something you know is vertical, like a door frame, to check the reticle again.
 
4535jacks said:
I have just mounted a new scope to a hmr and mounted it so when I mount the rifle in my shoulder the recticle is vertical. However it looks like the recticle is not level with the action which makes sense since my head has a slight cant.

Is it crucial to get the scope recticle perfectly level with the action or it is more important to mount the scope so the recticle is level when in the shoulder accepting that the rifle will be slightly canted to one side?

Thanks in advance,

Gary
Click to expand...

Hi Gary,

The most important thing is that when you shoulder the rifle either the reticule is level (if you intend to aim off for longer shots) or the erector tube travel is level (if you want to dial for longer shots).

If you are going to fit a bubble level, fit it to the scope to correspond with either the reticule or the mechanism (you can check both with a plumb line).

A level scope and slightly canted rifle to suit your anatomy will make pretty much bugger all difference compared to a level scope AND a perfectly level gun.

If it's just for normal sporting shooting then bringing the rifle up into the shoulder with a plumb line at 50 yards as a target and checking and adjusting the reticule would be more than good enough and allow you to naturally hold over without having to worry about cant.


Cheers





Clive
 
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