I’m not following. What are you measuring against… If the rifle is tilted, how will the plumb line indicate that.
Pic would be useful.
Glad you got me to do that because two of my scopes have a cant on them and I got to fix them.
You can see on the t-bolt that there is no flat on the action to set a spiritual level on… so, I use the lazy/expedient design of modern factory stocks (lack of toe and cast) to drop a plumb between centres of the butt screws. Not ideal but better than guessing the level. I guess you could put it in a vice and call it good enough but that’s how I got the cant on that scope.
You can see a good flat section on the Zasty action, so can use the magnetic level and the cap level to true the scope mounting.
(Fixed the cant on this one)
If you have a flat below the scope turret and a flat on the top of the action (or a rail), you can also use a steel rule to set the scope level as below. Obviously, this rifle doesn’t suit that method but there’s a pic for illustration purposes anyway.
Dammit… Late night posting after too many beers… though you were talking about mounting the scope…
I honestly don’t think I’d have time to check a scope bubble while hunting. Handy for longer range, I guess. Lots of people use them for f-class, etc but I prefer tuning my ‘internal level’ and training my eye to see cant.
You were correct the first time. I was asking about mounting.
1 Like
Ok… So I’m not a complete idiot, then… just mostly…
1 Like
I put a level and or a bubble level on the pic rail. I set up a brick on a rope hanging from a tree 500 yrds away and true the scope reticle to the 500 yrd plumb line when the rifle is level. I then fit a bubble level to the scope and make sure it shows level at this setting.
2 Likes
So I take it that plumb line is only useful when the butt has two screws holding the recoil/butt pad and the screws are aligned. Sort of old-school stocks if you will. Won’t work on most modern stuff? For example, one I have where recoil pad slides in to the chassis, rather than screws in.
I saw a video on YouTube that took this approach. Plumb line along the wall near the eye relief and torch shining through the objective lens projecting the reticle onto a wall. Then just fiddle with scope to align windage line to the plumb line.
Also this one is similar: https://www.youtube.com/watch?v=lQGM8Cn8lS8
You could just measure two center points on the butt plate. As I said, it’s just a work around I came up with to use when there is no flat surface on the horizonal plane to set a level to.
The advantage of doing at a long distance is it gives more precision. You scope reticle lines are much thinner in comparison to the object. Also just like MOA if you are out that little bit it is amplified at distance so you can get a finer adjustment.
Surprisingly I found and learnt that not all bubble levels are created equally. This was after buying a half dozen from China I got them off different suppliers and even in the cheap end there are differences. The Tube the bubble in is where it is all at. Are the surfaces straight? otherwise bubbles get stuck. The surfaces of the tube can have stiction which makes the bubble slow to respond. I am sure there is a heap more. I did find that there were amounst the good ones for builders some specs. Non for Rifle use. I have observed the issues on my guns. On my comp gun I have two and I am now used to how they behave and just where they sit when I am vertical.
At long range cant is a very important factor. If there is a mathematician in the house work this example. At 500 yrds the normal vertical adjustment from 100yrds is 8 MOA if you are 3 degrees off vertical what angle have you now added to your windage? By 1000 yrds the vertical compensation is now 29 MOA what have you done to your windage with the same 3 degree error?
1 Like
Vertical is vertical. Doesn’t matter whether your plumb line is immediately in front of the scope or tang sight staff, or 500mtr away. Unless you enjoy the walk, save yourself the time.
Yes, cant, or lack of it, is very important at almost all range distances. Think rainbow trajectories for heavy, or slow projectiles. 40gn rimfire @ 300mtr, or 500gn 45-70 @ 1,000mtr.
I disagree @oldAG when you wind your scope up to maximum magnification like it would be when taking a long distance shot, things like parallax, eye relief all become more sensitive it is at these settings and distances that it is best to set up your scope cant.
1 Like
So how do you guys ensure your rifle/action is true on the x/y axis before plumbing or leveling your scope? After all, it is pointless setting a level on a scope that is mounted to a rifle that is canted.
You are free to disagree, but, parallax will NOT change the cross-hair alignment, eye relief will NOT change the alignment, magnification will NOT change the alignment.
All that is required is that you can superimpose the cross-hair on your plumb line, at any distance.
I agree with all that you say there @oldAG but I think you can make a finer adjustment when it is lined up using a plumb line at distance and your scope adjusted in the same way as it would be taking a shot at that distance.
@Gwion I use a level across the top of the rail. However I am not sure it is that critical how the rifle is lined up. It is really about the scope retical being vertical so that the turret adjustments to the retical move the POI in the true direction.
Wrong. So wrong.
If what you are trying to achieve is accuracy, without cant, at extended distances then it is critical that not only is the reticle absolutely vertical, but that the rifle is also set up truely verticle. Rifle/action is done by placing a bubble level across the action, scope rail, or other known horizontal plane. Then, the scope reticle, or tang sight elevation staff, is aligned vertcal. There is NO point in aligning the reticle vertical if the action is not also vertical.
Imagine setting the scope up so that the reticle is rotated 45 deg clockwise. If the scope is maintained “level”, a shot at say 50mtr will be ball park. Maybe even zeroed at that.
But at, say, 500mtr the shot WILL be left and low. You not only have to adjust elevation but also windage. Similarly, rotated anticlockwise, the shot WILL be right and low.
It is ONLY when the scope and actual trajectory are aligned in the vertical plane that (excluding wind) adjustment of elevation is required.
I also place my level on the rail or flat of the action… when possible.
However, not all rifles have rails or flat spots on the action…
Im not talking about having the reticle at 45 degrees. I said that this must be vertical and the bubble level that you permanently on your gun keeps this vertical. so when you wind on or off elevation it keeps it in the vertical plane. However which way the action points under it is irrelevant. The rifle for all intensive purposes is round it doesn’t matter which way the stock is pointing.
The gunsmith may have indexed the barrel to get the natural bend of the rifle to be in the vertical so it is more easily disguised in the drop. But that bend is constant and can also be compensated by windage adjustment. The only purpose of the stock is for holding the action and most importantly managing the recoil to keep that to a minimum and parallel with the barrel. Not kicking up or sideways like some designs do.
sungazer-Scope mounting (and rifle levelling))
Im not talking about having the reticle at 45 degrees. However which way the action points under it is irrelevant. The rifle for all intensive purposes is round it doesn’t matter which way the stock is pointing.
The only purpose of the stock is for holding the action and most importantly managing the recoil to keep that to a minimum and parallel with the barrel. Not kicking up or sideways like some designs do.
My post said “imagine setting the scope up”, only to provide an extreme example. What I said remains true. Which way the action points is very relevant.
I agree that IF the scope and rifle trajectory are aligned in the vertical plane, it will not matter that the action/barrel assembly is not “vertical” in the stock. Shooting with a canted stock, if that’s how you want to make it fit your shooting style, is not a problem at all.
Maybe one of us is not getting their thought trajectory onto the forum accurately (sorry about the pun). For a good explanation, go here: - https://www.accurateshooter.com/optics/canting-effect-on-point-of-impact/