Leveling an action before leveling a scope.

[BoydAllen]

Boyd, I took a look at the link and could not figure out how this thing works, can you explain a little more please?Clyde

It has two pieces that slide in alignment and have a thumb screw to hold the setting. There is a level built in. You secure the rifle in a way that you can adjust its cant based on what the bubble of the level shows. One sliding piece has a V that rests on the top of the objective bell of the scope with the tool in contact with the front of the objective bell. The V on the other piece fits on the top of the barrel right under the front of the scope. With the Vs in contact, with the scope and barrel you can lock the setting with the thumb screw, and roll the rifle, or tilt the rife vise until the bubble is centered between the lines. This has the rifle so that the center of the barrel and the center of the scope are on the same vertical line. The advantage is that it does not depend on the the lug raceways or the scope base, but bypasses all of that to provide an independent and reliable to line up the rifle before rolling the scope to plumb the vertical cross hair. I hope that this helps you understand. After I wrote all of that, I found this. I should have looked first.
http://www.firearmsinsider.tv/gun-gear-reviews/exd-engineering-vertical-reticle-instrument
and this
https://www.rimfirecentral.com/forums/showthread.php?t=820225
and this video

 

[chkunz]

It has two pieces that slide in alignment and have a thumb screw to hold the setting. There is a level built in. You secure the rifle in a way that you can adjust its cant based on what the bubble of the level shows. One sliding piece has a V that rests on the top of the objective bell of the scope with the tool in contact with the front of the objective bell. The V on the other piece fits on the top of the barrel right under the front of the scope. With the Vs in contact, with the scope and barrel you can lock the setting with the thumb screw, and roll the rifle, or tilt the rife vise until the bubble is centered between the lines. This has the rifle so that the center of the barrel and the center of the scope are on the same vertical line. The advantage is that it does not depend on the the lug raceways or the scope base, but bypasses all of that to provide an independent and reliable to line up the rifle before rolling the scope to plumb the vertical cross hair. I hope that this helps you understand. After I wrote all of that, I found this. I should have looked first.
http://www.firearmsinsider.tv/gun-gear-reviews/exd-engineering-vertical-reticle-instrument
and this
https://www.rimfirecentral.com/forums/showthread.php?t=820225
and this video

Boyd, thanks for the explanation. This looks like a great tool. However my rifles are for position shooting and have a float tube under the scope so this may not work for my configuration.

 

[BoydAllen]

As long as your cant is consistent, and your vertical cross hair is parallel to a plumb line, I think that you should be fine.

 

[chkunz]

As long as your cant is consistent, and your vertical cross hair is parallel to a plumb line, I think that you should be fine.

That is what I am thinking. I found that I can judge the horizontal better than the vertical so I added a horizontal reference in addition to my vertical plumb line to my tall target.

I shot some groups with my tall target at 100 yards with my 1000 yard rifle in my normal prone (sling) position. My 1000 yard zero is 27 inches above point of aim at 100 yards. I found that my natural position resulted in a slight cant and if I did not pay close attention I was getting groups that were about two times as wide as high. I rotated my scope very slightly to make it more natural to get the horizontal reticle level and paid close attention to level and shot some ten shot groups. I am now getting nice round groups. I tried to level the scope with the rifle but gave up on that, too complicated with a match rifle in prone position and I am not sure that it maters. Thanks again for your reply, Clyde.

 

[Brians356]

I use a small carpenter's level to plumb my targets when I tape them to my portable target frame (which could be on sloping ground.) Assuming the scope reticle has been aligned to the scope / barrel datum line as shown in the video, I then monitor rifle cant through the scope by aligning the reticle itself with the leveled targets.
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[Brians356]

In the video Boyd posted, the bubble level serves no purpose in aligning the scope reticle with the scope / barrel datum. The rifle could just as well be lying on its side when performing that task. In the field, one could use the tool and its bubble level to monitor rifle cant, but it seems clumsy for that purpose, unless you're just adjusting bipod legs, then putting the tool away. What am I missing?
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[Brians356]

It has two pieces that slide in alignment and have a thumb screw to hold the setting. There is a level built in. You secure the rifle in a way that you can adjust its cant based on what the bubble of the level shows.

For aligning the reticle with the barrel / scope datum line (while shining light through the slit and scope) what purpose does the bubble level serve? The rifle could be on its side and the tool would still indicate alignment. What am I missing?
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[Shinbone]

I would probably set it up using the base and then do a tall target test. Or if you can find one, or have a friend who has one (as I do) this will get the job done.
https://www.brownells.com/gunsmith-...ers/vertical-reticle-instrument-prod6097.aspx
It puts the CL of the scope over the CL of the barrel. You can then roll the scope so that the vertical cross hair is parallel with a plumb line.

As Boyd indicated:

After trying multiple ways to level a rifle with none of them consistently reliable from gun to gun, the EXD Engineering leveling device is an easy and foolproof way to level almost any rifle. Once the rifle is level, the reticle's vertical line is aligned with a plumb line, either by looking through the scope at a plumb line, or by projecting an image of the reticle next to a plumb line (as done in the video linked by Boyd). This leveling procedure has a very high resolution and works perfect every time.

JMHO

 

[Shinbone]

For aligning the reticle with the barrel / scope datum line (while shining light through the slit and scope) what purpose does the bubble level serve? The rifle could be on its side and the tool would still indicate alignment. What am I missing?
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The EXD device works by referencing the reticle to an external vertical reference, such as a plumb line. To do this, the rifle must be level, which is where the bubble level comes in.

The reticle is not referenced to the long slit in the EXD device in any way. That slit is just for adjusting the two "V" sections of the device to sit on the rifle and scope properly.

 

[Brians356]

The EXD device works by referencing the reticle to an external vertical reference, such as a plumb line. To do this, the rifle must be level, which is where the bubble level comes in.

The reticle is not referenced to the long slit in the EXD device in any way. That slit is just for adjusting the two "V" sections of the device to sit on the rifle and scope properly.

Not in the video Boyd posted. There is no external fixed plumb line referenced. The retical is aligned to the slit in the EXD device itself, as it should be. The slit only is "projected" to a nearby surface by shining light through the scope, so that one can see both the retical and slit superimposed, to align them. (The scope is telescopic, not microscopic, so the slit is too close to the scope to see clearly enough otherwise.)

As I stated before, the rifle could be lying on its side to align retical with projected slit, so the bubble level is superfluous. Unless one leaves the EXD device permanently attached, for leveling the rifle in the field, it serves no purpose whatever. The video doesn't lie, nor do my own eyes.
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[Shinbone]

Maybe we are each talking about a different scope leveling devices? And, obviously, people are free to use their tools in any way that works for them. Maybe you have found an alternate way to use the EXD level? However, no where in the instructions does EXD talk about aligning the reticle with the slit. It only talks about aligning the reticle with an external reference, and therefor the bubble level is necessary.






There are other scope aligning devices that are specifically intended to align the reticle with a slit in the leveling device. But those devices use a slit much narrower than the slit on the EXD tool. For example:

JMHO, and to each his own.

 

[Shinbone]

Curious, I set up an LED light source, a scope, and the EXD device to attempt to project an image of the slit and reticle onto a white board:




Here's the projected image with the scope set at 3X power:




At about 10X, the LED light source itself, was resolved:



However, while sweeping through the power range of the scope, at no time was either the EXD slit or the scope's reticle resolved well enough to allow alignment of the two. At least that was the case to my eyes.

 

[Brians356]

Shinbone, my original comment was to Boyd, and specifically to the video he posted, where they project light through the slit. Using that method is much more precise than relying on a bubble level, which is notoriously imprecise. I could only assume the video followed the device's instructions, as the demonstrators never explained they were improvising and deviating from the instructions. I'm happy they did, because their light projection method is much more precise. Nevertheless, thank you for posting the actual instructions here, and clearing up my confusion about the need for the bubble level.
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[Shinbone]

Roger that. Anything to make the mundane tasks easier.

 

[Brians356]

Roger that. Anything to make the mundane tasks easier.

As you pointed out, a narrower slit is better for that projection method. Thanks again.
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[Zeke 225]

I mount the light in the front bell of the scope, or shine the light front to rear you can see the cross hairs better. Have a squared line behind the but pad, you can also adjust the power ring if desired

 

[Brians356]

Have a squared line behind the but pad, ...

Squared to what?
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[Zeke 225]

Squared to what?
-[/QUOTE
I just mount my rifle with scope on in my vise, I have a level or plum line against my wall behind behind the vise. And shine a light through the front lens and turn the scope until the cross hairs line up square

 

[Brians356]

Zeke, your vise clasping the rifle doesn't assure that the scope axis is directly above the bore axis, and the rifle is plumb. Probably close enough for most shooting.
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[fyrewall]

Good video - makes sense, combo of bubble level, V blocks for scope & barrel, and alignment of vertical reticle feature with light projected thru slit - now I have a use for some of my scrap aluminum. I gave up trying to use a bubble level on any part of the receiver and top of scope adjustment dial or cap some time ago, nothing seems square. For example, on a Ruger M77, MKII investment case receiver outside tolerances are +-.007, this may not seem excessive but when projected at any distance from a crooked surface the angular displacement could be magnified. On some of my pre CNC receivers (mid 1950's Mausers) making a precise outer receiver was of little consequence. Should my gadget work I have no plans to sell it.