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Old June 19, 2019, 06:14 PM   #1
stagpanther
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Introducing Stagpanther's "Short Target" tracking method

OK--let me get the disclaimer business out of the way right from the start: this technique maybe (probably) exists already some place, especially since I'm a complete novice to precision scope use, but I haven't seen mention of it anywhere and arrived at it through my own (often wayward) imagination. So bare with me if I'm merely repeating something that is already known--if not, try it out and let me know what you think.

Obviously, this is useful mostly with higher-power scopes that use precision retIcles similar to the tremor, Horus, Mil XT etc that have extensive hold over and side hold "hash" marks.

I just scored a Leupold 5HD 7 x 35 ffp scope with the nice 60 MOA impact reticle and I put it atop my savage 110 LRH in 338 Lapua Magnum. I've found a pretty good load but so far haven't been able to get out to longer range shooting. Before I do that though, I wanted to test the tracking ability of the scope. I first used Litz's tall target test, and then went online and found something called the box test, which I like because it also tests windage along with elevation tracking.

Mt results, though, were pretty poor using both techniques. In both cases, my groups tended to open up a bit the further I dialed up from zero. Furthermore, it was a bit tedious getting multiple verifications of distance to the target, and then making sure it was level. Lastly, going home and doing the math, I noticed my error margins were often in the neighborhood of 10% or more.

Was something wrong with the scope? If so, what? Or was it just me (which is what I usually default to)?

I was pretty frustrated, not to mention feeding an expensive reload diet to get inconclusive results. So I started my feeble brain thinking about what was inducing error, and the first thing I thought of was I was generally changing the position of the rifle or the trajectory of the bullet, even if ever so slightly. So I thought up a way (again, forgive me if this already exists, just haven't seen it mentioned in my research) to minimize barrel alignment change relative to POI. At the same time, I figured out how to test the scope's elevation and windage tracking as well as the reticle's accuracy in the same shot--and to top it off the results don't depend on perfect distance calculation to target.



Here's how it works:

1) pick your ladder group distances. For example zero, then 6 MOA up, 8 MOA up and 12 MOA up etc. These are the distances I used on my sample target pictured above.

2) Use the standard formula of range yds x dialed MOA x constant .01047 (you can change the formula for milrad). Using this formula, I came up with 6.282" or 6 9/32" for 6 MOA, 12.564" or 12 9/16" for 12 MOA etc.

3) Draw a vertical line down the target surface and draw a horizontal line that meets it at a right angle near the top of the target leaving room for "overshoot." This is the zero.

4) From the zero center, measure down the distances calculated for your MOA changes and add a horizontal intersecting line. In the sample target, the first lower line is at 6 9/32" etc.

Shooting the groups

1) Shoot the first group at the top intersection--I like to put a target dot there (and at all the other line intersections) to make it easier to see. If it's off a bit--that doesn't matter and there's no need to adjust the scope. Use the same zero setting and magnification value for all shots.

2) Shoot the next group at the chosen MOA rise. For example, on the target above I dialed up 6 MOA and aimed at the target dot on the 6 MOA line below the zero line. At the same time, I dialed windage 6 MOA right. Lastly, I aimed at the 6 MOA target dot with a 6 MOA hold-over and a 6 MOA right "side hold." To help illustrate, here is a picture of the reticle, where the two red lines meet is the aim point used at the 6 MOA target dot.



3) repeat for other MOA changes within the capabilities of your scope.

My theory is based on "low dispersion" of group impacts as opposed to group distance from zero as a measure of the scope's tracking accuracy. Yes, I could be totally off my rocker, won't be the first time.

Here's the target group at zero line with the first 3 shot zero group shot and then the second 3 shot 6 MOA elevation and windage offset. Even if the absolute zero and distance to target are a bit off, the error does not appear to affect the precision of the group. The group was shot using a bipod on my caldwell portable table--I shoot in a quarry which is almost impossible to get a table level, so I decided a bipod would make leveling the rifle a bit easier. The "flier" is the very first zero shot, but the rest of the group is pretty tight. Although I only tested a zero and 6 MOA group--I'm pretty satisfied that the mechanical as well as reticle tracking are working well. Obviously a couple more MOA groups would reinforce that.

Attached Images
File Type: jpg short-target1.jpg (121.1 KB, 292 views)
File Type: jpg short-target-group.jpg (133.7 KB, 290 views)
File Type: jpg Impact-60-MOA-reticle.2.jpg (39.9 KB, 268 views)
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Last edited by stagpanther; June 19, 2019 at 11:35 PM.
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Old June 19, 2019, 07:25 PM   #2
Doug Lee
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custom short range target

FWIW I printed a target to use when checking the iron sights on an M1 Garand, on a 25 yard range, the concept was simular to yours but the range graduations were inverted. POA stayed the same, POI hopefully changed with increased elevation on the rear sight.

On your scope, is that 60 MOA adjustable or fixed?
*
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Old June 19, 2019, 07:47 PM   #3
stagpanther
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Quote:
On your scope, is that 60 MOA adjustable or fixed?
Here's the skinny on the scope: https://www.leupold.com/scopes/rifle...hd-7-35x56-moa The 60 MOA impact reticle was only recently released.

Quote:
POA stayed the same, POI hopefully changed with increased elevation on the rear sight.
That's more or less the idea behind the tall target test--but the POI changes (and hence slightly the bullet trajectory). Then the measured change in distance relies on careful measurement and calibration of distance to target in order to reduce % error calculation. My method instead results only in adjustment to the scope's settings and reticle aim point used while trying to keep the barrel position relative to the target the same or as little changed as possible. It also does not require precise calibration using multiple measuring techniques of distance to target in order to get an indication of the scope's tracking accuracy--which is instead "revealed" by the precision of the shot group.
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Last edited by stagpanther; June 19, 2019 at 11:58 PM.
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Old June 20, 2019, 02:15 PM   #4
stagpanther
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Just for the heck of it--the overall group size including the flier was just under MOA--but when I broke out the three shots using the 6 MOA offset with hold-over and side hold--that appears to be a pretty good indication of good tracking.



Attached Images
File Type: jpg zero and 6 MOA.jpg (82.3 KB, 230 views)
File Type: jpg 6MOA.jpg (73.7 KB, 232 views)
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Old June 20, 2019, 06:41 PM   #5
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I don't think you've got enough data to confirm or deny anything just yet.
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Old June 20, 2019, 06:48 PM   #6
stagpanther
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Quote:
I don't think you've got enough data to confirm or deny anything just yet.
True--that's why I wanted to try to "lure" other shooters with similar scopes to try it out. ; ) I'm going to try it out with cheaper ammunition next.
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Last edited by stagpanther; June 20, 2019 at 06:58 PM.
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Old June 21, 2019, 08:40 AM   #7
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I'll be switching to my 6 Creedmoor AR build--it has a "middle of the road" prosumer grade FX 1000 ffp scope on it and won't cost as much to test. It also has "hold-under" hash marks on the reticle as well as about a third of it it's 60 available MOA dial down below zero. I still can't figure out to adjust the scope turret so it has an absolute zero stop and uses the entire dial range for up elevation--at least not without resorting to a canted rail.
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Old June 22, 2019, 06:39 AM   #8
stagpanther
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115 gr rdf's, Lapua small-primer brass and ramshot magnum. Curious to see how this works out.

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File Type: jpg 6mm-creed-rdf.jpg (208.6 KB, 189 views)
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Old June 22, 2019, 07:46 AM   #9
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115gr???
Did you make a 25 Creed???
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Old June 22, 2019, 07:50 AM   #10
stagpanther
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Quote:
115gr???
Did you make a 25 Creed???
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Nope--it's 243. Theoretically I should be able to balance them with fast enough twist and velocity--my McGowen barrel is 7 twist and I'm running these up as fast as I can--we'll see what happens.
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Old June 22, 2019, 09:08 AM   #11
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Stag,
Try some RL26.
My wife's 243 did great with it & 105gr bullets.
Hornady said they would not stabilize in her barrel, but had no issues out to 600 yards.
I guess if you throw a brick fast enough... Lol
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Old June 22, 2019, 10:01 AM   #12
stagpanther
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Quote:
Stag,
Try some RL26.
My wife's 243 did great with it & 105gr bullets.
Hornady said they would not stabilize in her barrel, but had no issues out to 600 yards.
I guess if you throw a brick fast enough... Lol
the 115 rdf's have some pretty impressive numbers.
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Old June 22, 2019, 01:33 PM   #13
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I just went out and tried a few loads based on ramshot magnum. As my luck would have, despite our forecast of sunny day with less than 10% chance of rain spontaneous thunderheads developed while I was setting up, in between lightning and downbursts I got a few groups off--the 115 rdf's seem to stabilize no problem in my barrel, even at lower charges/velocities. It was way too unstable for me to trust leaving the labradar out, so I'll have to re-test, but so far lookin good.

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File Type: jpg 6mm Creedmoor 115 rdf 38.5 ram magnum.jpg (173.9 KB, 175 views)
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Old June 23, 2019, 04:14 PM   #14
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I went out today and tried again--the day started out with the same sunny light winds as yesterday forecast, but just like yesterday it quickly overdeveloped and started gusting to 30+mph. Unfortunately I tried setting up my labradar which ended up in disaster--a gust blew it over (it was mounted on a tripod) and I'm afraid it's internals got damaged, the next load I tested with a higher charge than the last one recorded 300 fps less average than the previous load.
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Old June 24, 2019, 04:46 PM   #15
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Quote:
Unfortunately I tried setting up my labradar which ended up in disaster
Whats a Labradar? Maybe I need to get one.
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Old June 24, 2019, 07:14 PM   #16
stagpanther
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labradar is a Doppler "chronograph"--best device of it's kind in my biased opinion.
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Old July 3, 2019, 09:33 AM   #17
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Are you checking to see if the scope reticle axes are parallel with their E and W adjustment axes?

or...

Are you verifying the elevation adjustment axis is parallel with the vertical scope center to bore center axis?

You don't have to shoot bullets to check those out.

or, is it for something else?

What MOA method does the scope use; 1.0000 or 1.0472 inch per 100 yards?

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Old July 3, 2019, 09:56 AM   #18
stagpanther
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Quote:
or, is it for something else?
Mostly for mechanical check of turret accuracy and reticle accuracy--which, while you certainly can check it statically without shooting, I figure it's important to know that it's etched marks track "in sync" with the turret adjustments.
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Old July 4, 2019, 02:09 AM   #19
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If you want to test your scope tracking at 100 yards you might try the Ultimate Hunting Target.
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Old July 4, 2019, 04:55 AM   #20
stagpanther
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Bart--my particular gear and shooting style--as mediocre as they might be--I've noticed that even changing the rifle position (particularly elevation) to adjust to the POA can affect the barrel harmonics enough that POI shifts--that's why I sought to test minimizing changes in the actual rifle position. Maybe I'm nuts though.
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Old July 5, 2019, 09:21 AM   #21
Bart B.
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Quote:
Originally Posted by stagpanther View Post
Bart--my particular gear and shooting style--as mediocre as they might be--I've noticed that even changing the rifle position (particularly elevation) to adjust to the POA can affect the barrel harmonics enough that POI shifts--that's why I sought to test minimizing changes in the actual rifle position. Maybe I'm nuts though.
Changes in how you hold the rifle is what changes where bullets strike relative to aim point. The bore axis points to a different place when the bullet leaves. Bullets strike to the right if there is more resistance to recoil to the left. They strike high if the butt is lower in the shoulder

A free floating barrel's muzzle axis resonant and several harmonic frequencies are fixed by its shape, they don't change from shot to shot regardless of hold.

Many folks get better accuracy with rifles shot slung up in an F class prone position compared to a bench rest position. I am one.

Last edited by Bart B.; July 5, 2019 at 09:32 AM.
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Old July 5, 2019, 09:27 AM   #22
stagpanther
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Quote:
A free floating barrel's muzzle axis resonant and several harmonic frequencies are fixed by its shape, they don't change from shot to shot regardless of hold.
I assume you mean regardless in rifle position? For example when raising/lowering the rifle on my bag rests almost always induces a slight shift in POI--and that's entirely due to me personally how I manipulate the rifle?--go ahead, I can take it.
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Old July 5, 2019, 09:36 AM   #23
Bart B.
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Quote:
Originally Posted by stagpanther View Post
I assume you mean regardless in rifle position? For example when raising/lowering the rifle on my bag rests almost always induces a slight shift in POI--and that's entirely due to me personally how I manipulate the rifle?--go ahead, I can take it.
Yes.

Best example is shooting slung up in prone, right handed. Move your front elbow on the ground an inch to the left and the next shot will go right.

Another example, several people shooting the same rifle and ammo, each one's sight settings for range zeros will vary up to near 2 MOA across all.

Last edited by Bart B.; July 5, 2019 at 09:47 AM.
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Old July 5, 2019, 09:42 AM   #24
stagpanther
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Quote:
Yes
Dang! More work to do.
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