Scope or Rail Mounted Anti-cant Level

Greyfox

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Jan 21, 2008
Messages
5,675
Location
Northeast
I have used them mounted on the scope, rail, and tang in the case of my MPA chassis which come with a built in bubble level. I very much prefer the level mounted off the left side of the scope. Two reasons. First, there is minimal head/eye shift between the scope/ target when shooting. Second. Being attached and properly aligned with the scope, I can leave it in the position permanently knowing the crosshairs will be perpendicular when the bubble is centered.
 

Tiny Tim

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Joined
Jan 26, 2015
Messages
846
I have used them mounted on the scope, rail, and tang in the case of my MPA chassis which come with a built in bubble level. I very much prefer the level mounted off the left side of the scope. Two reasons. First, there is minimal head/eye shift between the scope/ target when shooting. Second. Being attached and properly aligned with the scope, I can leave it in the position permanently knowing the crosshairs will be perpendicular when the bubble is centered.
Thanks for the well thought out and expressed view.
 

Pro2A

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Joined
May 23, 2009
Messages
313
Like many individuals spend big money on the rifle and then cheap out on the optics. Most ignore the impact of shooter induced cant. Cant is critical to accurate distance hits. Reference Bryan Litz's ballistic book series for the impact of cant on down range impact between various calibers. All accurate custom rifles and expensive scope repeatability and adjustment accuracy are nullified by the variability in shooter cant error. No you aren't as perfect as you think. Levels are automatically assumed accurate down to the gnat's hair like anything spit out by a computer....but garbage in = garbage out. Levels need to be verified as any thing manufactured. Have checked most of the bubble levels sold by big name shooting manufacturers. The worst was a NF top ring half level........just a little useless......missing the whole level vial......case in point for any thing manufactured.!!!! The NF CS rep basically called me a liar until I sent pics of ring half sans vial in unopened bubble package. :) :) :) Levels vary greatly. Before being mis-treated in the field hanging off the side of the rifle, most are 1-3deg off from dead level as confirmed by very expensive, highly accurate machinists levels and dial indicating. Any level is probably better than no level as humans struggle to discern less than about 3 degrees (reference Bryan Litz ballistic books).....especially with common optical reference illusions due to a non-square/plumb world. If using a bubble level, I prefer a picatinny mounted version. You are interested in the relation between the scope reticle/adjustment mechanism and gravity. I like the Sig Tango6 scopes with the internal electronic level feature. Level is right in the scope view......no lifting/peeking to check level.....multiple accuracy settings down to about .2deg as I recall. But, the electronic level I really use the most is the SendIt unit by Long Range Arms. One will initially think it is too pricey at about $230 from Brownells, but really not even a rounding error in what most spend on shooting gear. And, it is easily moved between rifles.....basically nullifies initial cost out of the box versus multiple questionable accuracy bubble levels on multiple rifles. Per Litz, cant will nullify the expenditures on accurate shooting systems, so why skimp on the anti-cant mechanism. The SendIt features easily sensed 5 colored LED indicators......Green = Send It. Colored lights are more easily sensed than having to read a bubble position against scribed lines.....especially in failing light. Using 12 point multi-axis sensors adjustable in 5 sensitivities 1.0deg down to 0.2deg; can be mounted vertically, horizontally, upside down, left or right........and, intended shooter cant can be set. Just a really, really old guy's thoughts and spending comfort. One makes one's choice of warm fuzzy level....pun intended......and pays your money. Buy once; cry once; happy ever after.
 

Dragoon300

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Aug 22, 2020
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89
Location
49348
Generally the level should be mounted on the opposite side from your dominant eye, far enough forward to see clearly, so you can use you off eye to check level without loosing your sight picture. This works really well.

However, mounting off to either side does tend to get in the way, so levels that flip out may be the answer here.

My left eye has a retinal problem so I must use my right eye to check level as well as sight.
I found a rail mounted level from Knights Armament, that fits under my scope and I can momentarily glance down with my right eye to check it. I really like it and have gone to this on my rifles that have enough pic rail to do this.
20200706_203313.jpg
 

badthirtyone

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Joined
Nov 26, 2007
Messages
325
Location
Denver Colorado
Generally the level should be mounted on the opposite side from your dominant eye, far enough forward to see clearly, so you can use you off eye to check level without loosing your sight picture. This works really well.

However, mounting off to either side does tend to get in the way, so levels that flip out may be the answer here.

My left eye has a retinal problem so I must use my right eye to check level as well as sight.
I found a rail mounted level from Knights Armament, that fits under my scope and I can momentarily glance down with my right eye to check it. I really like it and have gone to this on my rifles that have enough pic rail to do this. View attachment 243159
That's a sweet setup. Gotta have the rail space available, though. I generally am lacking real estate for something like that at the back of my gun. For all of the options that mount or reside under the ocular lens, that's probably the coolest one that I have seen.
 

Canadian Bushman

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Joined
Jan 24, 2012
Messages
1,814
Location
Houston, Texas
I use a EXD engineering scope level to align the scope over the barrel.

With that leveled i use a plumb bob to align the scopes reticle and tracking to the exd.

When those agree. I mount a MSP scope level to the scope tube.

Now when i align the scope level in the field, i know my scope is tracking straight up and down through the center of my barrels od. Assuming the bore is close to concentric and not too bent.

I use MSP because they are very simple, un-cluttered, rugged, dont snag on packs cases and clothes, and often resolve much finer than much more expensive levels.

I dont use rail, ring or other fixed levels because i cant adjust them.
 

264MHC

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Joined
Sep 3, 2019
Messages
192
Location
Eastern NC
I really like my flatline ops articulating levels. I prefer the tube mounted ones because once it’s set for that scope, it’s done and the scope can be moved around without disturbing it. I have one that is rail mounted as well but even as low pro as it is, it will not fit under a scope with low rings, at least the ones I’ve tried. I do love how they fold out of the way and can be adjusted perfectly once mounted to the rail/scope, but I have found that the adjustment screw needs to be loctited to stay in place as I noticed my reticle was no longer level at the range one day when the level said I was. Put some loctite on the screw and re-adjusted and all is well now.
 

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