MATH RIDDLE: sight adjust from 5m to 10meters

[atomicgale]

MATH RIDDLE:
1. Currently sighted in at 5-meters on my in-living-room pistol range (shooting air rifle targets).
2. Saturday is CMP air pistol match at Camp Perry/Anniston AL - obviously at 10-meters.
3. What is exact number of clicks on rear sight of Steyr EVO to adjust elevation?

I don't have time this week to "Field Test" at 10-meters, so hence, this triangulation problem is tendered for consideration here on Target Talk.

Any recommendations?

[crankythunder]

Dear Atomicgale:

I do not want to discourage you but there really is no easy way to adjust your sight for different ranges. While I do not do air pistol, I go from 25 to 50 yards in Bullseye and from 50 foot to 50 yards to 100 yards in smallbore.

Each scope or sight will have a different number of clicks to go from each range, and in smallbore, where I adjust to 3 different ranges, I need to remember my last adjustment to take acount the number of clicks for the slop. while each sight is similar, every one is different and while I have the "dope" written down, it was acquired with a hefty amount of experience. It would take a number of range trips to confirm that my sight is zeroing with the prescribed amount of clicks before I would head to a competition without verification.

Make some time, head to the range and shoot the distance, write down your observations and most importantly, find out the slop, and then go shoot the daylights out of the target.

Regards,
Cranky

[Rover]

"Cranky" makes sense. I guess your problem can be solved by shooting the sighter target(s) you'll be given at the start of the match.

After you've zeroed based on one sighter target, use the other for a backer for your match targets. After you've fired 20 or 30 shots you can fine tune your zero based on the group center. Tattoo the sight change clicks backwards on your forehead and put a mirror in your gun case to read it.

[gimgim]

One interesting file I've found on the net, has targets scaled down for various distances and with the bull offset so that you can shoot without having to re-sight the pistol every time: http://www.luftvapen.info/Downloads/mal ... resize.pdf
Never used it, because it seems a lot of work (I practice sometimes st 5m, but do not score, just look at the group) and sighting the pistol seems a skill you want to improve anyway.

[Gwhite]

It will depend on your hold, but the adjustment may be quite small.

For example, if you shoot a center hold, because the bore is below the sights, the pistol is actually shooting up to hit the center of the target. Assuming the additional drop due to gravity is negligible, the shots would go higher at 10 meters, and you would have to adjust down. In actuality, a pellet traveling at 500 feet per second will drop about 0.8" in 10 meters (actually a bit more as it slows), and the two effects will tend to cancel.

With a typical sub-six hold, you are shooting up a lot more, but you are also tipping the pistol down. The downward angle will be roughly the same when the target is scaled & moved out to 10 meters, so you may still need to adjust down.

The only practical experience I have with this issue is shooting free pistol. I've found that going from 50 feet to 50 yards I usually barely have to touch my sights. One or two click of elevation is all it takes.

[stephen_maly]

This is where your shooting diary comes in. You leave the pistol sighted for 5 m, then make the necessary adjustments on your sighting target at the match, and record that information for future use. The exact number of clicks depends on the velocity as well as the pellet weight. If you want to same a little time, check your manual to find out how much each click moves the point of impact at 10 m. If it is the same as an LP10, it would be 1.2 mm / click (if the rear sight base is not extended). Make a grid on a computer, with the vertical and horizontal lines spaced every 4.8 mm (5 mm is close enough). Make the grid about 10 cm by 10 cm, then print it on a clear piece of transparency film. Keep a target face up on the bench in front of you when you shoot, with the grid on top and one corner at the point where the shots are hitting. Every complete grid line is four clicks, and smaller than that you make a judgement call.

[Gwhite]

The scoring rings on an air pistol target are 8mm apart. The Steyr Evo is listed as moving the shot 1.2mm per click, so it's ~ 7 clicks per scoring ring.

[atomicgale]

Gwhite has a great point: Figuring in a SUB-6 HOLD as a baseline for "Line of Sight."

There's more to this:

Here's the constants I'm using:
Steyr EVO: +/_ 1.2mm adjustment vertical per click (@ 10meters)
Velocity = 500 ft/sec = 152.4 meters/second
Gravity = - 9.79595 meter/sec^2 (at Copperhill TN longitude of 34.989N, altitude = +1,470ft)
Height = +18.5mm (from center of bore to top of front sight)

Note: The pellet DOES NOT travel 10 meters! (Only your front foot is at 10 meters. You must subtract the length of your arm + length of barrel.)

And proceed with calculations. Now that I'm properly using Gwhite's Sub-6 Hold as true line-of-sight, my previous solution got crushed . . . .

I HAD an answer. Now re-working problem. Until then, let's hear Target Talk's hypothesis . . . .

[Bob Foth]

Looks like you'll need to come down about 15 clicks when you go from 5m to 10m.
It is not very sensitive to how far out your hold area is (i.e. center vs. six vs. sub-six)
It is more sensitive to the average pellet speed which I am making some assumptions on...

[atomicgale]

Well . . . THAT was a DISASTER!!!

Yes folks, back from the CMP Match in Anniston . . . wished someone would just steal my pistol so I could be done with the horrific episode . . .

First, I was placed in Lane 5, next to our World Cup Gold Medalist James Hall, and about the only thing I didn't screw up was shooting HIS target by mistake. Basically, EVERY SHOT was dreadfully high, over-flying center mass by several orders of magnitude.

What I learned:
1. I suck
2. Practicing at 5-meters & trying to use physics on Target Talk to adjust to 10-meters is a VERY BAD IDEA.
3. Don't get up at 2am & drive 4 hours to the match
4. Remember to eat breakfast
5. They make you wear shoes! ( Here, in Tennessee Appalachia we shoot barefoot.)
6. I'm friggin' BLIND . . . borrowing Uncle Fester's reading glasses didn't go so hot.
7. Get the pistol sighted in PRIOR to the match
8. There are exactly 120 clicks of vertical sight adjustment on a Steyr EVO - I used 'em all . . . .
9. When lessons #2-8 fail, refer to lesson #1


SCIENTIFIC QUESTION: Are the non-rotatable STEYR front sights a different height, than the stock Rotatable 4.5mm Steyr sights that come on the pistol?

Basically, I had my rear sight elevation adjusted all the way to the Stops, but still was significantly high on target. So was this operator error, or a mechanical malfunction?

While significant empirical evidence exists to confirm the pistol-operator totally sucks, we're trying to eliminate all possible mechanical variables prior to the next CMP match on October 12th.

We'll let Target Talk decide!


Sign up for CMP here:

http://thecmp.org/competitions/

[thirdwheel]

Now that made my morning and brought a big smile to my face, I guess most of us have been there when we first started out in competition and have done all of the above several times over, you know what to do now and it's not throwing your nice pistol in the lake. Although training at shorter distances can be done at home - (here in the UK 6yd has quite a following), there is no substitute for training at the full 10m. Yup get proper shooting lens blah, blah, blah. etc, etc, etc.
Are you twiddling the the correct adjustment screw and in the correct direction, look at the manual but if it is going high turn the elevation to H and you can see the whole rear sight going down - just in case - to make the point of impact move in a particular direction you need to move the rear sight in that direction, teaching your grannie to suck eggs I know but so many do not understand this. The Steyr markings have fooled many in the height of battle.
If after calmly working through your sight alignment problem properly at 10m and it is still shooting way too high, post again and I will let you know how to fix it, but make sure you understand the logic, if going too high turn towards H and if too low turn towards T!

[jscot111]

Make sure the lower edge of the rear sight isn,t bottoming out on the grip. You can click and the sight actually doesn't move.
Scott

[-TT-]

... make sure you understand the logic, if going too high turn towards H and if too low turn towards T!

This. German pistols do things this way. Italian pistols do the opposite.

This thread may help: http://www.targettalk.org/viewtopic.php?f=4&t=60290

[Rover]

Pound your shooting hand with a BIG hammer.

It will feel SOOO good when you stop.

[atomicgale]

A BIG Hammer . . . I had been smashing my hand with a Moonshine jar. Thanks Rover!

We now return our Target Talk audience back to mathematical physics . . . .

Okay, another user error here. I had measured the height of the 5mm non-rotatable sight at .380, and the stock 4.5mm sight at .388 (it's slightly higher, as it's cantilevered), a difference of 8-thousanths.

Somehow, while I was hallucinating from fatigue early this morning, I used .08" (instead of .008") & multiplied that by the "Number of Sight radius's in 10 meters," to derive the change in impact.
Hence, my incorrect calculation:
Height difference = .08"
Sight radius (metric) = 345mm
Change in impact = .08" x (10m / .345m) = +2.32 inches, which would explain the "Overflying Phenomenon."

Conclusion:
WRONG! Properly using .008" yields about a quarter inch difference. Hence, we can rule out front sight height as cause of yesterday's catastrophe.

Back to the "Operator Error" hypothesis . . . .

[thirdwheel]

I use Swiss, Italian and Austrian pistols on a regular basis for competition in anger and the LP50 has tripped me up more than once when I'm in the zone and relying on my subconscious to drive the outcome. I now look at the word bei on the sight adjustment to mean "too" and that helps to transpose the meaning.

[Rover]

So you did everything you possibly could to fuck yourself up (apart from the big hammer), EXCEPT shoot a few at your sighter target and see what was happening?

Oh, waaahh!!!

[Gwhite]

<Snip>
Basically, I had my rear sight elevation adjusted all the way to the Stops, but still was significantly high on target. So was this operator error, or a mechanical malfunction?

If you are shooting that high, I suspect either serious damage to the pistol in transit (it's happened...), or operator error. If you are using a conventional sub-six hold, you may be losing focus on the front sight and looking at the target. There is a natural tendency for the muzzle to drift up when you look at the target, and it doesn't take much to launch them off the top of the paper.

At 5 meters and with bright lighting, the target may be close enough that you can sort of keep everything in focus. At 10 meters, you HAVE to focus on the front sight. The target will be blurry, but it's not moving.

[atomicgale]

Rover:
Yes, I did take 17 (yes, Seventeen sighters) & my pattern looks like a big "EXCLAMATION POINT" with the untouched 10-ring being the dot & a tall, narrow vertical string above the dot.
No Rover, although I tried, I didn't do EVERYTHING "to F-myself up" . . . for example:
1. I left the Tennessee-Hill-Billy Moonshine at home
2. I didn't drive half-way there & remember I forgot my pistol
3. I did have air in the cylinders (both of them)
4. I didn't leave the pellets at home either
5. MOST IMPORTANTLY = I WAS THERE.

GWhite:
You are correct (again), in that my Abomination was a combo of full operator error, lack of properly preparing my pistol, and lack of experience.

The CMP Range is FANTASTIC! Perfect conditions. Yes, target was full-focus & front sight blurred.
I had no idea how good the computer interface they provide works. It's great! But, never having seen this set-up before took some attention away from shooting the pistol. Adapting to full match conditions was additional learning curve.
THE STAFF AT CMP IS ABSOLUTELY FIRST-RATE, PROFESSIONAL, WONDERFUL!
Yes, due to their support & help I've already signed up again for the October match.

So, we'll discount my Over-Flying the target due to: a. Super nervous shaking hand, b. Couldn't keep sight-pic steady, c. Muscle tension on trigger control, d. Not familiar enough with my pistol.

Everyone:
I would encourage anyone to sign up for the next CMP MATCH on October 12th. Matches at Anniston AL, and Camp Perry OH.
Trust me, it's a wonderful time.

[Gwhite]

<snip>
Yes, target was full-focus & front sight blurred.

That's your problem in a nut shell. The standard fix is to add a positive (Plus diopter) correction to your vision setup. That will move your relaxed focus closer to the front sight, and can even make it impossible to focus on the target. For most shooters, the best place to start is to add +0.75 diopters. The mechanics for doing that depend on whether you wear glasses, contacts or have good vision without correction.

For the last two, one inexpensive approach is to get corrective safety glasses. If you already wear corrective glasses, then a clip on lens will do the trick. This web site has a bunch of options: https://shootingsight.com/product-category/lenses/