Bubble not-level

[ThunderMug]

I have yet to find a pic mounted bubble level that is consistent. Yes, those top 4 are US Optics $85 each. I have two more of them that read randomly as well.

I am aware the mounting screws are diffent. That is not the issue. If I swap them around, they still read the same. So don't start that shit.

 

[voltage]

Nice

 

[JF_Idaho]

Yeah, that's ugly. I go for the scope tube mounted levels. Match it up to a plumb reticle and call it good.

 

[bluesulphur]

The world's smallest level has never seemed like a very accurate tool to me, but I'm not a long range guy with a gun or a bow. It always seemed like framing a house with a torpedo level.

 

[wapitibob]

They shove the bubble into a clearanced hole with a little glue and move on to the next one.

 

[IDVortex]

I've never been into the bubble levels just from my experience with tiny bubble loves with construction lol.... maybe Stabila should start making some, id trust those.

 

[HawkCreek]

Obviously, all reading the same.would be ideal. But how often is anyone swapping different levels onto theor gun?
If the bubble is off but it's off the same each and everytime you'd have your dope card made up with that error but it would still be consistent.
Or am I wrong in my thinking?

 

[IDVortex]

Obviously, all reading the same.would be ideal. But how often is anyone swapping different levels onto theor gun?
If the bubble is off but it's off the same each and everytime you'd have your dope card made up with that error but it would still be consistent.
Or am I wrong in my thinking?

Would you not need to test to see how the rifle sits at a true level then gauge what the bubble level says? Because if the gun is still not leveled, and you go off your dope, would it still not be as accurate? (I think I'm over thinking what you're saying)

 

[flyfisher117]

I bought my first and last rail mounted bubble. It's close but not as close as i would like. I'll stick to the scope tube ones.

 

[LongWayAround]

Obviously, all reading the same.would be ideal. But how often is anyone swapping different levels onto theor gun?
If the bubble is off but it's off the same each and everytime you'd have your dope card made up with that error but it would still be consistent.
Or am I wrong in my thinking?

My thoughts exactly. Everything has error.

If you level your scope according to the bubble, it should not really matter because it will be repeatable.

Whether one puts that bubble on the rail or the scope itself also seems irrelevant. Either way, it's a reference point and if it doesn't match the reticle plumb, you will experience error.

For the OP's picture, I would not feel good about the top four. The bottom five seem "close enough" to me.

I would be curious to see how the UM bubbles compare to those pictures

 

[Shortschaf]

It is completely unnecessary to have two different levels read the same, and manufacturers know that.

So they don't make them read the same. To do so would be extremely difficult.

 

[ThunderMug]

Yeah, that's ugly. I go for the scope tube mounted levels. Match it up to a plumb reticle and call it g

Obviously, all reading the same.would be ideal. But how often is anyone swapping different levels onto theor gun?
If the bubble is off but it's off the same each and everytime you'd have your dope card made up with that error but it would still be consistent.
Or am I wrong in my thinking?

You are correct on impacts at a set distance. But as soon as you dial your turret for elevation you will have issues due to linear trajectory. Without an accurately reading bubble level it is hard to know when the rifle is truly level.

I mount a bubble level to my pic rail. Then I hang a plumb bob from an 1/8" black string at 20 yards against a white wall. Next step with the level reading flat, I rotate the scope in the rings until the vertical crosshair is exactly parallel to the string.

I have tried lots of "scope leveling kits" They rarely work because they do not account for 3rd axis.
They only way to confirm 3rd axis is to ensure that the bubble level is 90 degrees from the axis of the bore.

The only way I have found to do this with a scope mounted to the pic rail is by mounting a pic rail bubble level that is accurate.

 

[ThunderMug]

p.s. I have never had luck getting any scope mounted level to read accurate unless I matched it to a 3rd axis compensated level that was 90 degrees to the bore.

It is completely unnecessary to have two different levels read the same, and manufacturers know that.

So they don't make them read the same. To do so would be extremely difficult.

 

[Shortschaf]

p.s. I have never had luck getting any scope mounted level to read accurate unless I matched it to a 3rd axis compensated level that was 90 degrees to the bore.

That is unnecessary. I get that some people are ocd about it, and that's fine. But to share some numbers for others who might think the "perpendicular to 3rd axis" is a big deal:

My general guess is that anyone can eyeball it to within 3°

3° off of perpendicular to 3rd axis comes out to an angular offset of 0.1" at 100 yards.
Or 1" at 1000 yards.

1. Most people don't have a zero that is closer than 0.1" of center to begin with
2. And even more people will never call wind to within 1" of the bullseye at 1000 yards

Conversely, if your scope is 3° off from your level, you are off by 0.4MILs (14 inches) at 1000 yards with a 6.5 creed


Scope-mounted or rail-mounted, the numbers are the same

 

[wapitibob]

3rd axis doesn't matter, until it does, same for bows. Shooting on level ground it makes no difference but for a Sheep hunter, he'd be smart to level his rifle along the barrel axis first than level horizontally. Otherwise, that bubble is going to run to the side when he starts shooting up/down hill.

 

[signing off]

For grins, I could send off any level for calibration. A four foot level owned by a bowling alley was confirmed to be accurate and had certification to prove it.

 

[Shortschaf]

3rd axis doesn't matter, until it does, same for bows. Shooting on level ground it makes no difference but for a Sheep hunter, he'd be smart to level his rifle along the barrel axis first than level horizontally. Otherwise, that bubble is going to run to the side when he starts shooting up/down hill.

Maybe I need schooling on what everyone is calling "3rd axis"

My assumption is that "90° to the 3rd axis" was that if you extended the vertical reticle downward, it would pass perfectly through the bore's center.

If that's not what you mean, please help me

 

[wapitibob]

I use "3rd axis" as I would with a bow sight which may be incorrect for a rifle. I believe the bubble level needs to be 90 deg to the longitudinal axis of the rifle, when looking down on the rifle from above. I assume most are 90 deg but if one isn't, the bubble will run to one side when shooting up or down hill.

 

[Shortschaf]

I use "3rd axis" as I would with a bow sight which may be incorrect for a rifle. I believe the bubble level needs to be 90 deg to the longitudinal axis of the rifle, when looking down on the rifle from above. I assume most are 90 deg but if one isn't, the bubble will run to one side when shooting up or down hill.

Under your definition, what you say is absolutely correct.

I think that @ThunderMug is talking about what I described in post #17