Scope Cant

[eric n]

CK32
What happens if my gun isn't perfectly straight up and down?

Your wind zero will move when you dial elevation.

A level rifle actually felt very uncomfortable to me, it took some work for me to break the habit of self induced cant... I couldn't have done it without a level.
I still catch myself canting occasionally even though I know what level feels like now.

[JTROKS]

Depending on the degree of cant the bullet will land towards the side it is canted. That's if there is no wind and your scope is squared to rifle's bore.

[JMP]

Killshot, I went shopping for a bubble level that would sit low and fit my scope. The exact B-square at brownells that you linked is what came up for me. But, nearly all the reviews are negative, citing that it is a cheap Chinese POS that is constantly breaking. Truthfully, for $14, I'd expect no less. The one from LaRue that's build over an arc seems to be the only one I saw worth beans as the arc would give it meaningful sensitivity, but I saw nothing that would fit my rigs. At this point, if I wanted one, I'd simply get a cheapo home depot level and mount it appropriately on my rifle. The cosine lever would be nice, but your rangefinder should provide that.

I've had plenty of success at hitting IPSC targets over 2,000 yards so far in 3 different cartridges and calibers, and I am adding a couple more in the near future. Those targets are less than 0.7 MOA at 2,500 yards, which make them a difficult shot, which is why it is important to be consistent. Like I have said, there is not a person on the planet that can guarantee a hit at 2,500 yards with any rifle on his first shot, but most can get pretty close. One would simply use the sighter to adjust.

I can see where some might like them in rapid fire at intermediate distances when you are shooting off a moving bipod. But, for the rifles that have the horsepower and ballistics to shoot to extreme levels, you are not going to be shooting off of a floppy bipod if you want results. I might want one if I were shooting off my old style tactical Accuracy International bipod that provides for massive adjustments quickly at shorter ranges, but I haven't had an issue holding vertical.

Thinking about it, I am wondering if some of the folks having issues are higher magnification shooters using a small field of view where it's harder to keep and orthogonal hold. Just a thought.

Like, I've said before, they certainly aren't going to hurt you, but I am not sold on the advantages for shooting at extreme distances as your rig is set to compensate for this.

[JMP]

Also, for folks getting too much movement on a flimsy bipod, they make different feet. For, example, it would be silly to shoot off of ice cleats on summer dirt as they'd dig in too far. Make sure you have maximum surface area on the bottom of your bipod feet in a pattern that will grip your shooting surface. Admittedly, I shoot most of the time off of a shooting mat that has bipod pockets so it's a bit of a cheat compared to real tactical operation.

[postal]

No doubt about that, I've shot critters while set up downhill using an Atlas with one leg waaay longer than the other and having a bubble helped keep things level shot-to-shot. Didn't help my back any, though.
Surprisingly, I didn't need a cosine indicator when shooting downhill.

So.. you cant tell level looking at something from left/right.... but have a built in sense of angle looking downhill?

Thats exactly backwards from me.... I can see level left/right but no idea the angle of down slope to a target without a cosine indicator or a slope dope/mildot master.

[JMP]

Thats exactly backwards from me.... I can see level left/right but no idea the angle of down slope to a target without a cosine indicator or a slope dope/mildot master.

However, your range finder gives you the angle of inclination, which is nice, so you just hit it with a Cosine function and multiply by straight line distance. But, for quick adjustments, the Cosine indicator is nice. There's a nice German level with Cosine indicator as well that I am looking at. Obviously, if I put something like that on, I might as well do it right and not put some cheap Chinese bubble that I might as well get at the 99 cent store and mount myself. Those little bubbles only tell if you are WAY off. You know, you may need to flick the tube a few times to get the bubble to move even after you cant. Like I was saying, I noticed LaRue had one that was pretty slick as it was build on an arc, which would give a lot more precision than the cheapo bubble levels that are not accurate to the centiradian, which you really need.

Generally folks do not shoot at such an inclination to make it that big a difference. Take a slope of 0.1 radian, which is pretty steep, and at 1,000 yards, you are only 995 horizontal, so most folks do not perceive the difference in angular adjustment.

Now, pretend you are shooting from the top of a tall building that is 1,000 meters high straight down at a target. Your angle goes to the extrema -pi/2 radian, and your 1,000 yard dope is trash as you get Cos(-pi/2)=0.

[postal]

However, your range finder gives you the angle of inclination, which is nice, so you just hit it with a Cosine function and multiply by straight line distance. But, for quick adjustments, the Cosine indicator is nice. There's a nice German level with Cosine indicator as well that I am looking at. Obviously, if I put something like that on, I might as well do it right and not put some cheap Chinese bubble that I might as well get at the 99 cent store and mount myself. Those little bubbles only tell if you are WAY off. You know, you may need to flick the tube a few times to get the bubble to move even after you cant. Like I was saying, I noticed LaRue had one that was pretty slick as it was build on an arc, which would give a lot more precision than the cheapo bubble levels that are not accurate to the centiradian, which you really need.

Generally folks do not shoot at such an inclination to make it that big a difference. Take a slope of 0.1 radian, which is pretty steep, and at 1,000 yards, you are only 995 horizontal, so most folks do not perceive the difference in angular adjustment.

Now, pretend you are shooting from the top of a tall building that is 1,000 meters high straight down at a target. Your angle goes to the extrema -pi/2 radian, and your 1,000 yard dope is trash as you get Cos(-pi/2)=0.

I wish I knew who this was...... Whaddya think the dope is for this shot? I think distance is of no importance.....





I hope he has a bubble level...... or he aint gonna hit it....

Note the harris style bipod sitting on the cliff face.... I wonder if he has those ice cleats on it.....

[ar15barrels]

Those little bubbles only tell if you are WAY off.

The bubbles I use are accurate to 3/4 of a degree.
It's quite easy to see if the bubble is centered or on either side too.
You can hold 1/4 degree accuracy quite easily and that's WAY accurate enough for what we are doing.

[ar15barrels]

I believe that's Jacob Bynum.

I wish I knew who this was......

You dope for a straight-down shot should be about -1 mil, just like how you adjust -1mil when you roll the gun 90 degrees.

[JMP]

The bubbles I use are accurate to 3/4 of a degree.
It's quite easy to see if the bubble is centered or on either side too.
You can hold 1/4 degree accuracy quite easily and that's WAY accurate enough for what we are doing.

Is your bubble made in China like the ones you need to flick to get it too move because the air pocket is too large in relation to the total volume and length?

Sent from my D6616 using Tapatalk

[ar15barrels]

Is your bubble made in China like the ones you need to flick to get it too move because the air pocket is too large in relation to the total volume and length?

No.
Mine are US made.
The bubble is less than 1/3 the length of the vial and moves quite easily.

[postal]

I believe that's Jacob Bynum.



You dope for a straight-down shot should be about -1 mil, just like how you adjust -1mil when you roll the gun 90 degrees.

I saw the pic a while back... always wondered who it was.... Jacob is someone that could pull this off.....

Hey, do you contour barrels? flat taper to med palma ish?

[ar15barrels]

Hey, do you contour barrels? flat taper to med palma ish?

Nope.
Send it to whoever made it.
Most charge $40 to recontour a blank they made.

[CK_32]

Man! You guys make me want to dust off the bolt gun and remember how horrible a shot I am

[JMP]

No.
Mine are US made.
The bubble is less than 1/3 the length of the vial and moves quite easily.

Yep, I really like the design of how you made and placed that bubble. I don't mean to sound like a bubble snob, but what folks aren't understanding is that not all bubbles are created equally. Most of the ones marketed for rifles are poorly designed.

You want a sensitive bubble, and there is some Chemistry and Physics involved in the matter. You want a bubble that is designed to be of relative correct size to the tube for optimal sensitivity. Then, it needs to be composed with the right fluid. If you have something that is too low viscosity and not enough surface tension, then, the bubble can "break" into smaller bubbles. On the other hand, if you have it a fluid with too much viscosity, the bubble will not be reactive enough.

Then, on big long range sticks, you can't have something flimsy.

This bubble was recommended to sit close to the tubes for $15:

http://www.brownells.com/optics-mounting/optic-accessories/scope-anti-cant-devices/bubble-level-prod1758.aspx

Just look at it, what a POS.

the comments are (starting from the most recent and in consecutive order (not cherry picking).

ordered two in spite of recent reviews

Having had one permanently installed on my custom 10/22 for a few years now, I was surprised at all the negative comments, and decided to try a new to see how it worked. I ordered two and installed them on a custom 30BR rifle and the other on a long range 30-06. So far they've held up well. Even if they don't REALLY level the rifle (which they may or may not do) they allow for consistence in the cant, or lack thereof, for every shot. And consistency is the name of the game. It works for me. Luisyamaha San Juan, PR

Cons Inaccurate, Poor Construction
Describe Yourself Competitive Shooter
Was this a gift? No
Bottom Line No, I would not recommend this to a friend

I bought 2 of them and both broke. Don't waste your time or money. This product is Chinese made garbage.

Cons Poor Construction

craftsmanship issues

Simple device that torques on to the rail. Noticed some arching of the housing when tightened. You MUST mount this on first then level your reticle to this bubble for accuracy. In my case, plastic bubble housing came loose and fell out due to AR recoil. You'll get what you pay for - but hey, it's a bubble for the budget shooter.

bubble part fell out

I was using it on the front rail of my RRA AR. It was a pretty cool setup in that I could keep my right eye in the scope and the left eye on the bubble. I couldn't get it to be perfectly level with the rail, so I slightly canted my scope at the same amount. I liked the thing at first. In fact, ordered a second one. However, at the range yesterday the bubble part fell out when I tipped my rifle to the side. Not very inspiring. You also have to pack your rifle very carefully or it would easily be damaged in a case.

Describe Yourself Law Enforcement/Military
Was this a gift? No

bubble fell out

Not a bad item except the plastic cylinder that holds the bubble fell out and had to be glued back in.

Pros Easy To Install, Inexpensive
Cons Poor Quality
Best Uses Plinking
Describe Yourself Law Enforcement/Military
Was this a gift? No

poor quality

I mounted it to an AR-10 and it warped as soon as I mounted it. When I tried to remove it to put on another rifle, the threads hung up. The metal appears to be very soft. I traded for a better design level that mounts to the scope.

Metal broke...

This is a nicely priced item that is cheaply made. It is a great concept, but the metal it was made from snapped at the attachment point. Not something to stake your life on, but for non-military/LEO use, it is just fine. Wish they made it in a sturdier package for the same price...

broke after first range trip

This is my 2nd purchase of this Bubble Level. The original unit is still on my bolt gun and never had any issues in 3 years of use and abuse my recent purchase for my ar10 its mounted behind the front scope ring. I went to the range today fired 6 rounds to zero my rifle and when i went to weight the rifle in our range office, the plastic bubble fell out and ended up on the floor.. a 308 kicks, but not that bad...... reglueing as we speak

Didn't fit on my mount

This item didn't fit on my mount at all. Because of this, the level was crooked and defeated the purpose of having one of these. I played around with it to see what was wrong with the fit and it just seems like there wasn't enough metal machined out of it to make it fit on my Badger Ordnance mount. I am returning it to Brownell.

Bottom line, pick out a good bubble with a Cosine dial if you want one, or make your own like the one ar15barrels installed with the nifty location. Just like all optics, I'd avoid the Chinese makes...just a tip for those in the bubble market.