Anybody Ditch the Bubble Level?

[mxgsfmdpx]

Have any of you gone out and tested a severely canted reticle on a 12” target versus a “level” reticle on a 12” target at realistic hunting yardages? Say 400 yards and in?

I’m talking shoot 5-10 shots canted, and then 5-10 shots leveled and compare.

What happens?

How much cant does it take to cause a miss at 400 yards, that would have been a hit in say a true 2 MOA shooter/gun combo shooting in the mountains (this is a very skilled shooter/gun combo by the way, despite what the internet says).

 

[HuntHarder]

Have any of you gone out and tested a severely canted reticle on a 12” target versus a “level” reticle on a 12” target at realistic hunting yardages? Say 400 yards and in?

I’m talking shoot 5-10 shots canted, and then 5-10 shots leveled and compare.

What happens?

How much cant does it take to cause a miss at 400 yards, that would have been a hit in say a true 2 MOA shooter/gun combo shooting in the mountains (this is a very skilled shooter/gun combo by the way, despite what the internet says).

Isn't it true that a 1* cant @ 1000 yards is 5"? Essentially making a 1* cant at 500 2.5"? I am not sure if the math holds true, but if it does, a 5* cant at 500 yards should be 12.5." I have never verified this, but on paper it makes sense to me.

 

[mxgsfmdpx]

Isn't it true that a 1* cant @ 1000 yards is 5"? Essentially making a 1* cant at 500 2.5"? I am not sure if the math holds true, but if it does, a 5* cant at 500 yards should be 12.5." I have never verified this, but on paper it makes sense to me.

It depends on the bullet and the air like everything else ballistics related…

As an example, I did this a couple weeks ago with a few shooters in the mountains using my 308 and heavy, high BC bullets.

I had them address the gun, get on target, the whole works with not checking a level bubble.

Guys with higher experience were within roughly 5 degrees of level and usually better. Some newer shooters and two shooters unfamiliar with anything other than a range style shooting bench were occasionally outside the 5 degrees of level but usually better than 5 degrees of cant.

At 400 yards, a cant of 5 degrees, with that bullet in that air, the math showed that it represented just below 2” of error.

So unless you’re calling the wind to within 2 MPH at 400 yards (which is next to nobody) and are a true 1.5 MOA shooter/gun in the mountains (next to nobody) you aren’t really shooting the difference between a perfectly level gun and a gun with slight cant.

In saying that. All of my guns have a level bubble and I always do my best to ensure the gun is not canted. In some situations (long distance/being well beyond 5 degrees of cant, etc.) it can make or break a killing shot.

 

[Carl Ross]

Isn't it true that a 1* cant @ 1000 yards is 5"? Essentially making a 1* cant at 500 2.5"? I am not sure if the math holds true, but if it does, a 5* cant at 500 yards should be 12.5." I have never verified this, but on paper it makes sense to me.

It isn't linear to distance, it's basically linear to the elevation correction. Thus, it is exponential as distance increases.

Without doing the math I believe the numbers @mxgsfmdpx is sharing. At most hunting ranges, probably not an especially big issue.

That said, I have the same level in the same place on all my rifles, and checking the level and adjusting cant is part of my shot process.

 

[mxgsfmdpx]

I've tried to use them. Seems they always move on the scope tube and then when I think I'm level I'm way off. I took them off.

If I could find one that doesn't snag on stuff, stayed put, and wasn't a hassle I might use one.

Then there are some credible people who say they are not needed. Thomas Haugland did some testing and found it just slowed him down and it did not affect his field shooting.

So...I'll keep it simple until I prove to myself if I need one or not. Or find one I can see while addressing the rifle for the shot.

My personal experience is closely aligned with what Thomas was observing in the video. Using an IMU mounted to the gun, which measures real time pitch roll and yaw 100 times per second, and using 4 or 5 different level bubbles, there was roughly 3ish degrees of discrepancy between what was “level” between them.

Most regular field shooters with good fundamentals have shown to be able to hold within 5ish degrees of level. Verifying quickly with a bubble for more awkward shots is still ideal for me as steep varied terrain can mess with perception.

 

[Dan Carey]

All my rifles have them. When I look at them they are always in the middle, maybe I need a better level.

 

[mxgsfmdpx]

I played around with a scope a couple years ago that had an IMU on board and displayed the degrees of can’t digitally in the bottom of the sight picture. Think like a digital level bubble.

Kind of neat, but the scope was a tank, and I didn’t trust the accuracy of any IMU with a small enough form factor to sit cleanly on a scope bell (at least not at that time). Plus most cheap IMUs are susceptible to long term drift and need recalibration quite often.

I think the tech will be there soon if it’s not already to be reliable enough, and could be a cool option in the future But it’s likely just something else to break on a scope in long term use as the IMU would be required to not ever shift, and we barely have any scope options that actually work properly as it is.

 

[HuntHarder]

It depends on the bullet and the air like everything else ballistics related…

As an example, I did this a couple weeks ago with a few shooters in the mountains using my 308 and heavy, high BC bullets.

I had them address the gun, get on target, the whole works with not checking a level bubble.

Guys with higher experience were within roughly 5 degrees of level and usually better. Some newer shooters and two shooters unfamiliar with anything other than a range style shooting bench were occasionally outside the 5 degrees of level but usually better than 5 degrees of cant.

At 400 yards, a cant of 5 degrees, with that bullet in that air, the math showed that it represented just below 2” of error.

So unless you’re calling the wind to within 2 MPH at 400 yards (which is next to nobody) and are a true 1.5 MOA shooter/gun in the mountains (next to nobody) you aren’t really shooting the difference between a perfectly level gun and a gun with slight cant.

In saying that. All of my guns have a level bubble and I always do my best to ensure the gun is not canted. In some situations (long distance/being well beyond 5 degrees of cant, etc.) it can make or break a killing shot.

Thanks for the explanation. I have honestly never really experimented with it. All my long range rifles wear levels and I do my best to remember to glance up and get close to level before shooting. When it cools off and hunting season winds down, I may experiment. As the years go on, I am getting more and more into shooting. The technicals of it interest me. I love tinkering with reloading, knowing most of my tinkering gives me almost no gain. It's that little bit of gain, that keeps me going back tho.

 

[Chris in TN]

Isn't it true that a 1* cant @ 1000 yards is 5"? Essentially making a 1* cant at 500 2.5"? I am not sure if the math holds true, but if it does, a 5* cant at 500 yards should be 12.5." I have never verified this, but on paper it makes sense to me.

You can calculate the angle between the rifle bore and scope axis for any given zero range; the angle grows steeper with longer distance zeros. You can then extend the geometry past the point where the scope and bore intersect (say, 15 yards ish with a 400 yard zero) and think of it as if you were rotating the rifle around the axis of the optic to create two cones; one representing the space between the rifle and scope axis and the point of convergence; another cone mirros the first but on a much larger scale as you go past 15 yards out to 400. As you rotate the rifle clockwise the bullet begins to scribe an arc to the right and downward. If you have a bore height of 1.5" and your boreline crosses LOS at 15 yards with a 400 yard zero, your bullet will veer to the right by ((400/15)*1.5))-1.5 or 38.5" to the right at 400 yards and will also be low by the same amount, if you turn the rifle 90 degrees.

So you end up with a series of shots, if you were to rotate the rifle completely, that would make a circle with a radius of 38.5" with the top center of the circle being your normal level hold POI.

(I'm spitballing the numbers here but they're close for the typical 6.5cm-ish cartridge)

So a circle with a radius of 38.5" has a diameter of 77" and a circumference of 242" and if you divide that 242" figure by 360 you can see that each degree of right or left cant should move the bullet by about 0.66" at 400 yards. At first the error is mainly left/right but as you cant the gun more the error increasingly scribes an arc low to either side.

As noted above by someone else, it takes several degrees to move you by 2" at 400 yards. So, no, it's not a huge deal, but errors add up.

 

[Catterz]

No. Usually distracting but necessary