Question about Tall Target Scope Tracking Test

[Baron23]

HI guys - I'm pretty dang sure I know the answer to this, but I have thought that on many subjects in the past with some truly terrible (and costly) results!

I bought some Hide scope tracking test targets from Box to Bench and just read the instructions that they have online.

Those instructions say to start at the bottom of the ladder!!??

I presume that these instructions assumes that I'm going to actually shoot at this target, i.e. keep the POA constant and watch the POI march up the ladder.

But, I borrowed a heavy Targets USA test fixture with the pic rail from a friend of mine and my objective is to do the test as Frank (@lowlight ) outlines in his video.

Basically, I want to take my shooting out of the equation and just see if the scope independently tracks up/down accurately.

So, my view is that I level the fixture side to side (really, level my horizontal reticle line) and raise the elevation (with the scope elev back at zero) of the fixture until my reticle is on the TOP end of the ladder and I should see the reticle decline down the ladder with each mil of elevation.

I just thought to check in with you folks to make sure I'm not missing something in my thinking here???

Thanks in advance for your time to reply

 

[Jimgal62]

The target must be at exactly 100 yards from the elevation turret.

 

[Baron23]

The target must be at exactly 100 yards from the elevation turret.

Yep, I do know that. But thank you for taking the time to reply.

 

[Nik H]

You are correct.

The POA moves down as elevation is added. Start at the top

When you are shooting, you aim at the bottom. The reason is simple. As you add elevation, the POA still moves down but you have to adjust the rifle so that the muzzle rises so as to move the POA back to its original position. As you add elevation, your POA never changes but since the muzzle is constantly adjusted higher, the bullet impacts higher and higher up on the ladder.

 

[Baron23]

You are correct.

The POA moves down as elevation is added. Start at the top

When you are shooting, you aim at the bottom. The reason is simple. As you add elevation, the POA still moves down but you have to adjust the rifle so that the muzzle is higher to move the POA back to the original position. As you add elevation, your POA never changes but since the muzzle is constantly adjusted higher, the bullet impacts higher and higher up on the ladder.

Thanks Nik. I felt pretty dang confident that I had a good understanding of this but....this is my first time trying it.

I'm heading out tomorrow. I have a range finder (tape won't due as the land is not level at all) and believe I can position the scope fixture/scope on the bench to get exactly at 100 yards....to the accuracy of the Vortex RF.

I believe that if I'm a yard or two off, that there is some math that can be done to account for the extra distance???

In any case, I'm heading out tomorrow morn to give it a try. I'm sure I'll discover quickly what I don't know! haha

Thanks for the reply.

 

[Nik H]

As long as you know the exact range, it does not have to be 100 yards exactly. You just have to know what it is. A good ballistics app will calculate the error but so can you, it is easy to do

 

[Baron23]

I went to the range today with the Sniper Hide scope tracking targets purchased from Box to Bench. Very nice quality targets. Heavy paper and very crisp and clear printing.

Because we have these...ah, kind of crappy target boards at my local club, I bought a 2' x 4' piece of thin plywood at Home Depot and a handful of .99 spring clamps. Stapled the target to the plywood, clamped the plywood to the target board, and with a long level I got the vertical line....well, vertical.

A friend has the Targets USA scope fixture that he bought on the Hide from someone for $100!! Wow, now they are $350 for the complete fixture.

So, I'm glad he loaned it to me.

Along with crappy target boards, this small club also has kind of crappy benches with old carpet that they nailed to the top. So, a 2' x 2' piece of thicker plywood was needed to give some stability to the test fixture.

The test went wonderfully well. Took just a bit of fiddling around to get the fixture leveled (well, the scope leveled via the fixture) and on the proper zero mark. And from there it was very easy. I dialed up a mil at a time and checked and went up to 10 mils (most you can do with 36" target that I had) and it tracked straight down the line and was spot on for each mil. Returned to zero and damn, spot on again. Did this 4-5 times then did mil left and right at top, middle and bottom and again IMO the scope tracked perfectly.

Now, I did take a pic with my old ass iPhone 6 which was the only non-success of the day. Actually, it was an epic fail. LOL

Remounted the scope on the rifle this evening and check level against a plum bob and all is good. Tomorrow I'll shoot and check the zero. I expect it will take a tweak or two to get it right again (def do this test before going thru the bother of mounting and zeroing your scope if you can).

Thurs or Fri I will do the test with the Leupold Mk 5.

Oh, I guess this is important....you cannot use a long tape to measure out 100 yrds at this club. These targets were on our 100 yd line but the intervening ground is anything but level and there is a small berm behind the 50 yd line with the 100 yd targets back and higher (bit up a slope so you shoot over the 50 yd line). I took my Vortex RF and it varied between 101 or 100 so I'm guessing its just a small bit over 100. But I sure didn't see anything that I could note as an induced error during the tracking test.

It was a bit of work to just find out that the scope I have been using is good....but now I have confidence in it up to 10 mils of elevation which should cover this .308 out to 900 yards which is longer than this particular deer gun will be shot.

I will leave you with a final thought, an old friend of mine was once asked by a mental health professional what he thought an obsession was and he replied "Ah....something to do???" haha...I think of that often when playing with stuff like this. Hey, its not OCD, its just attention to detail! LOL

Cheers

 

[Baron23]

So, tall target test round #2.

This time took the Leupold Mk V, 5-25 x 56.

Same basic set up including the fact that I really needed to use the same range target board #5 (out of ten) as it afforded me the room I needed to mount the target properly (see pic in above post...same thing this time). But, there was a fella on bench #5 whaling away with an AR-10 (he seemed to be practicing for the next battle of Khe Sanh) . I asked him which board he target was on...he said #1!! sigh

So, I had to take a bench a bit further down and still mounted my tall target on board #5 which introduced just a slight amount of slant range.

With the Viper test, my Vortex RF flickered between 100 and 101 and this time with the slight addition of slant, it was a solid 101. RF is the best I can do due to terrain issues and 50 yd berm.

I mention this because as I scrolled down the target (dialed up scope elevation) I started seeing a bit of overshoot creeping in and culminating in about .1 - .15 mil too much elevation at 10 mils on the turret (i.e. it was just a bit below the 10 mil line on the target...really right on the bottom of the boxes at the end of the lines so about 1/2" at 100 yds)

So, I figure part of this error is from being just a bit too long (which will indeed result in what looks like a bit of overshoot as I dial down the tall target) plus nothing is 100% accurate and I believe in Frank's video he may have mentioned that 1-2% error is not at all unusual in a scope (but I may be misremembering...but I did watch it three times!! haha).

The scope returned to zero correctly each of the 5-6 cycles I went through and windage, 1 mil left and right, was accurate from top to bottom.

My current view is that this scope is fine and nothing to worry about, moving on.

So, am I thinking about this right?

@lowlight - haha...Frank, I just want you to know that somebody looked at your scope tracking video and Tall Target Tested, Bro!

@Nik H - hope you don't mind my tagging you but you have been very helpful to me on this subject and others so I am interested in your view of this. Of course, that doesn't mean you have any obligation to do so!

Cheers