Rifle Scopes My "straight up" test (testing for scope cant - pic)

[garandman]

That's what it was called on a TV show I saw, anyway. According to the TV show, if the scope was canted, the hits would trail away from the line as the scope was dialed up for distance.

Here's the deal.... 100 yard target. Line was leveled with a bubble level. Placed magnetic bubble level on a flat on top of the scope ring. Zero to the big black dot. Since I have a mil / mil Leup MK4, I went five clicks up for each round fired. This turrets are set to zero at 200y so I actually went to a -5 to get to 100y. Then to 0 for the second round, +5 for the third round, etc.

At +25 is a 3-shot group. Then I jumped to 40 for a 2-shot group, then to 45. Hash marks on target are inches. 40 / 45 click shots I just tried to lay the crosshair perfectly on top of the line on the target. 45 click is scope setting for a 700y target.

The idea is to test for scope cant. Here's the pic...

Observations:

(1) I need to go a click right to a near to perfect zero.
(2) Next time I do this, it will be with a black circle as an aiming point, not a blacked out dot. I often lost the crosshairs on the black dot.
(3) Its hard to check for level / keep the gun perfectly level, while looking at crosshairs.
(4) I think my scope is OK, I guess...

 

[thrusty]

Nice test. Will give this one a try.

 

[garandman]

Nice test. Will give this one a try.

My question is "Will this test really actually prove scope cant / level?"

 

[z71rat]

I have used this same tracking testing method before. It does work for sure. I also use it to make sure that my vertical clicks actually measure out correctly to make sure the values are true. It is a good method, and I recommend it highly.

DK

 

[thrusty]

My question is "Will this test really actually prove scope cant / level?"

It will prove several things:

1: Scope tracking/function
2: Cant of rifle of a dead level scope
3: Crooked scope if you're not canting the rifle and shooting naturally and consistently.
4: Ability to double check your dope... Ie: You should be shooting around 4" high for your 6.5 Creedmoor 300yrd dialed elevation based on your AVG velocity @ 100 yrds....for 100 yrd zero. (example here - numbers may not be exact).

 

[Lowlight]

Its nothing new, the line deal, that is for sure,

As I noted, there is a "line" to test your scope with the SH Target, it also has "dots" on the line for dual use, as you don't always need it for scope tracking.

The SH Targets tests the impacts against the line, spacing or tracking of the clicks, and the reticle, as you can use either. It's calibrate in both mils or MOA with the grid behind it too,

I designed to do this with my target as checking your scope is important. I don;t get how you (garandman ) don't understand the how the lines are similar after I pointed it out to you the other day. A line is a line, a line with dots is just an added bonus

Here it is again, the "line" an old idea...

You can run the scope up every 1 mil to hit the dot, you can use the dots for targets later, you can use just the bottom dot and run the scope up any way you like to see how it follows the line.

Some scopes do have a curve in their travel, especially at the top end, others have odd tensions in their tubes, others have issues tracking correctly and still some might have a wrong reticle

 

[scsims]

I've done this test as described in one of Bryan Litz's books every time I mount a new scope. He called it the "Tall Test" in the book.

 

[Lowlight]

if you take the XLR Class at Gunsite you test your scope on a ruler like this... they use a laser and dial the scope, then they use the calibration option in Field Firing Solutions to test the scope tracking to the 100ths

Horus also sells these types of targets that are vertical for testing a scopes adjustment... I suppose unless it's on TV or in a book it never happened before the publish date or airing.

 

[scsims]

if you take the XLR Class at Gunsite you test your scope on a ruler like this... they use a laser and dial the scope, then they use the calibration option in Field Firing Solutions to test the scope tracking to the 100ths

Horus also sells these types of targets that are vertical for testing a scopes adjustment... I suppose unless it's on TV or in a book it never happened before the publish date or airing.

That's what I was trying to demonstrate. He saw it on TV I read it in a book, and I'm sure many, many guys have done the test just for the common sense of the necessity of vertical tracking when your dialing for distance. If I was smarter I would have done it before someone else had to tell me about it.

 

[xring11]

I learned something from this thread.
I'll try it at the range sometime soon.
Thanks!

 

[alfson]

The thermometer target was developed for the M1 Garand to determine your comeups for match shooting. It was designed to be used with a 50yd zero and M72 match ammo and has calibration lines labeled 200,300,500,600, and 1000. It is currently available from The National Target Co. I was told by an old Marine team OIC when I was a young Marine that the ones we were using had actually been developed about 100 years earlier and just updated and calibrated for the M1.

 

[jdgray]

My question is "Will this test really actually prove scope cant / level?"

Yes it will, but it wont check if the scope is out of line with the bore. The aiming dot no doubt, must be small enough to get a precise aim. Once the target line is drawn vertical with a level, your scope reticle is all you need to keep vertical with your target line. The extra level on the turret is not needed. To check your scopes alingnment along the bore, you shouldn't need to add windage as you dial up as you shoot at longer distances. If your dead on with windage at 100yrds, it should be dead on at 600yrds. No wind is a must!!

 

[kisskaren]

Nice test!

 

[garandman]

Made this magnetic bubble level to stick to the scope ring... all materials purchased at Lowes for about $7...

Pictured with a 308 round for comparison...

 

[captcoop]

Assuming that the test target is mounted with a " vertical " line. A plumb bob test with the crosshairs is the way to go. Here's what I did, put a level on my 20 moa rail (scope removed). Got a dead bubble on the rail. Locked in my sinclair bipod. Added scope and rings, placed an 8 lb down rigger ball on a piece of 3/8 white rope. Aligned crosshairs to the white rope. Assuming the 20 Moa rail is level with the receiver and bore .

 

[Pinecone]

1) I would use a square box as an aiming point. Like the OCW targets posted in SH. Very easy to keep your cross hairs centered.

2) If you have the line perfectly vertical, and you keep your vertical stadia on the line, the only thing you are testing is that your scope tracks properly.

3) If you have the vertical stadia aligned with the vertical line, your scope is not canted. And it doesn't matter if the rifle is canted. You could rotate the scope 45 or even 90 degrees in the rings and this would still show ONLY your scope tracking.

4) If your vertical stadia is not aligned with the vertical line, you are testing nothing.

 

[cjd223]

I add a horizontal line that intersects the vertical line at 90 degrees. It is easy to make certain your horizontal cross hair lines up with the horizontal line. I aim for the intersection of the two lines. Next I turn the elevation turret up two full turns and shoot again. I use a level to make certain the target is perfectly level.

 

[pappy42]

I've been too lazy to run this test; maybe this thread will get me off high center.

 

[bluto77]

If you line up your vertical stadia line to the vertical line on the target, and only focus on that, it should only be testing the tracking and will not tell you if your reticle is canted.

If you add a perfectly 90 perpendicular horizontal line to the target and line reticle up with both lines only (ignoring if rifle is level), then you're still only testing tracking and will not be able to tell if rifle is canted.

Seems like you would have to make sure rifle is being held level to the earth, then hold center of crosshairs on 100 yd dot on target, NOT lining vertical stadia up perfectly with vertical line, then run the test, and that should show you if the scope is canted. Of course, you would already know before shooting in this Instance, as you would be able to see if the vertical stadia lines up with vertical line on the target when rifle is perfectly level to the earth. This would tell you if the scope was canted in the mount.

The first 2 methods would tell you if something was wrong with the actual reticle/internals of the scope.

Right??? Am I thinking of this correctly? This is making my brain hurt. Seems like it should be very simple to figure out. But the more I learn around here, I'm finding out there is less I actually know!

 

[Pinecone]

The point is, there is no problem if the scope is canted on the rifle, as long as you have the scope level/vertical when you shoot.