GTA
All Springer/NP/PCP Air Gun Discussion General => "Bob and Lloyds Workshop" => Topic started by: lloyd-ss on February 04, 2018, 10:35:52 AM
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This has been bugging the heck out me >:( for a long time and I finally found the answer hidden in Hawke Chair Gun Pro. ;D
yes, yes, I am sure a bunch of you already know this, but I didn't, and I have found that if I have a question ???, there are other folks that are wondering the same thing.
If you have, for example, your .22 shooting 900fps zeroed in at 50 yards, but your velocity spread is plus or minus 15fps (total spread of 30fps) how much variation is that on the point of impact on your 50 yard target?
Well, Chair gun pro does it for you. ;D
First, enter all your info like you normally would and you get the usual table and graph.
Then at the top of the page, click on Toolbox on the menu bar.
Then click on Vertical Stringing.
Then fill in the box that says "Variation, fps".
Then look at the new chart at your sight-in distance and it will show you the plus and minus vertical difference in inches. VERY COOL!! 8)
For example, that 22 at 900 fps +/-15fps, at 50 yds the variation is +.18" to -.19", so a total variation of 3/8".
But, if you check it out at 80 yards, the total variation grows to almost a full inch. And at 100, you better get the variation down to +/-5fps.
:o Very good info to have.
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I did not know that! Thanks for sharing this info, great stuff!
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This is for the desktop version right?
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This is for the desktop version right?
Yes, installed on my laptop. The one where you have to have Java installed. version 4.3.6 is what I have.
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Allrighty... thank you, i will install today....
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Also interesting to run that again, but adding in a 3 MPH miss-guess of the wind (like you estimated 8 MPH, but it turns out to be 11MPH).
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Also interesting to run that again, but adding in a 3 MPH miss-guess of the wind (like you estimated 8 MPH, but it turns out to be 11MPH).
Thanks. Something else I hadn't thought of. I also figured out why wind at 180 degrees doesn't cause any drift. :-[
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Allrighty... thank you, i will install today....
I got a "no JRE found" error and had to install Java, too.
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And yet ... folks wonder why us Field Target folks are so anal about low ES figures, using regulators and just so dang convinced it's all worth the effort.
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Wow I hadn't a clue about all that! Great info to learn thanks!
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Lloyd
Thank you, for this info, very interesting, will do more researching.
Question for you,
What did you find with the wind at 180* or 360* when shooting?
New to this AG arena......
I know that the POI can be slightly higher or lower, depending on the direction etc.
This is shooting from PB's and long range, when holding the same POA.
Tia,
Don
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Allrighty... thank you, i will install today....
I got a "no JRE found" error and had to install Java, too.
Thank you sir!
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And yet ... folks wonder why us Field Target folks are so anal about low ES figures, using regulators and just so dang convinced it's all worth the effort.
I was totally clueless as to how big a difference it made when you are shooting at any kind of distance. I am sure you are chuckling Scott, cause this is old news to you FT guys, LOL.
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.......Question for you,
What did you find with the wind at 180* or 360* when shooting?
New to this AG arena......
Tia,
Don
Some of the target shooters will have to answer that question, 'cause I sure am not one! ;)
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Thanks Lloyd, I have wondered how people figured this out in the past.
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That "Vertical Stringing" widget is very handy.... it's been in ChairGun for many years, over several versions....
I guess how low you think you need the ES depends on how accurate your gun is, and how good you can shoot.... I use a 4% ES as "acceptable" at 50 yards, 3% at 75 yards, and 2% at 100 yards.... because I figure the vertical dispersion will be lost in the group size anyways.... I guess is you are REALLY good, with a SUPERB gun, you might want to cut that in half.... but for the way I shoot (even off the bench).... those guidelines work for me.... If you can shoot within 1/2 MOA, here is the ChairGun data converted to a graph for pellets with a BC of 0.030, at various velocities....
(http://i378.photobucket.com/albums/oo221/rsterne/Ballistics/ES%20vs%20Range%20BC03_zpsepwassf5.jpg) (http://s378.photobucket.com/user/rsterne/media/Ballistics/ES%20vs%20Range%20BC03_zpsepwassf5.jpg.html)
Got a lower BC pellet, like a wadcutter?....
(http://i378.photobucket.com/albums/oo221/rsterne/Ballistics/ES%20vs%20Range%20BC01_zpsbhlciqxo.jpg) (http://s378.photobucket.com/user/rsterne/media/Ballistics/ES%20vs%20Range%20BC01_zpsbhlciqxo.jpg.html)
Or are you shooting a bullet at longer range?....
(http://i378.photobucket.com/albums/oo221/rsterne/Ballistics/ES%20vs%20Range%20BC10_zpsqy6yloe5.jpg) (http://s378.photobucket.com/user/rsterne/media/Ballistics/ES%20vs%20Range%20BC10_zpsqy6yloe5.jpg.html)
Note that a 2% ES is the same as plus/minus 1% from the average velocity....
Bob
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Good stuff! Thanks.
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Since you brought up wind and error in range estimation, here is a chart comparing the importance of those to a 4% ES.... The straight green line is 1 MOA.... I can't remember what BC I used for this chart.... so consider it kind of "generic"....
(http://i378.photobucket.com/albums/oo221/rsterne/Ballistics/Trajectory%20Errors_zpsyjgic01f.jpg) (http://s378.photobucket.com/user/rsterne/media/Ballistics/Trajectory%20Errors_zpsyjgic01f.jpg.html)
Note that the greatest error is caused by misreading the wind by just 2 mph.... At the same range where a 4% ES becomes a 1 MOA error (~ 77 yds), making just a 2% error in estimating the range overtakes the ES as a greater error factor.... The reason the black line representing the range estimation error goes back to zero at about 30 yards is because that is the top of the trajectory I used to create this chart....
Bob
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Bob, Thanks for taking the time to do all those graphs, and I bet they were in your archive, LOL.
They really show how much more tolerant a hi vel gun is to variations in ES.
Shooting accurately is too much like work. :P
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Yeah, I wrote about this a couple years ago, and the charts were in Photobucket.... BTW, I won't be losing access to my charts and pics there.... but it will cost me $100/yr.... ::)
Incidently, the best .22LR target (subsonic) ammo has an ES of 2.5-3% over a box of 50.... Most commercial HiVel .22LR is over 5% ES.... and some is over 10% ES.... :o
Bob
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Wow, great stuff y'all!
I've had my fun with unregged guns, but as my shooting ranges get longer these days, well, you know, the less fun it becomes...
I wish I had the time to drop regs into all my fav PCPs right now, lol, but I don't, so thank goodness for guys like y'all and Rocker1. David is gonna put one of Lloyd's valves into mine and a reg and see what can be done for power over 16 shots.
The stringing on my Kral NP-01 in .25 is apparent at any range, ha ha, she's a rainbow launcher, lol..
If I dig the Prod upgrades enough, my Kral will be getting a new valve and reg next, me thinks! I hate to farm out work I can do myself, but I am just too busy to get anything done with anything air gun related here very soon, and I am dyin' to see what these new valves can actually do, soooo, off they go to Florida!
Y'all are doing awesome stuff y'all, really. Very impressive work. Bravo!
:-) chickie
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That pretty cool Lloyd
I have been using chair gun for a few years now and had not used the vertical stringing feature yet but never used that feature of char gun. I do shoot FT with several guns so now I can add vertical stringing to the variable I need to account for in my range cards. I knew it was a variable but was not aware that it could be calculated in chair gun until now. Probably only barely touching the surface of what chair gun is truly capable of doing. I guess as they there is always something new to learn in this sport/hobby.
Mike
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so far, have not been able to tease out the hands on difference between 3% and 1 1/2% velocity variation.
Have to belive there is a difference....just can't shoot a set of targets for 20 shots...(can be 4x5 shot or 2x10 shots, whatever you prefer...but no less) that show it.
I can barely tell 4% from 1.5%.
likely it's the chimp-behind-the-trigger (biologic error), wind (environmental error), pellet variation (mechanical error), or what-have-you.
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Yes ... the anal reality is that in FT what too often kills a possible point is SPLITS that strip a pellet of it energy even tho most stills passes threw the KZ hole.
Be it close in or out near 55 yards this smallest of ES could very well be where a shot drops just enough to get caught on the edge of KZ hole ... maybe not :o
It is in large ... a game of confidence that your guns placing pellets where aimed and one of your ability to get it there. If one can eliminate even an 1/8" at 55 yards & less so as you get in closer .. it could spell come matches end a few more points ;)
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Bob I'm personalty not computer savory, But my son say's You can move your data & pics out of Photo Bucket to another source instead of paying a ransom fee, lots of info on goggle https://www.google.com/search?ei=9Lh3WvGROOiatgXd55S4Bg&q=how+to+move+my+photos+out+of+Photobucket&oq=how+to+move+my+photos+out+of (https://www.google.com/search?ei=9Lh3WvGROOiatgXd55S4Bg&q=how+to+move+my+photos+out+of+Photobucket&oq=how+to+move+my+photos+out+of)
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Getting the photos out of Photobucket is not the issue, in fact I already have them all on my home computer.... The problem is uploading them all onto a new hosting service where every photo or chart will now have a different URL than what I posted previously.... I have, over the years, posted on about 8 different Forums, and currently still post virtually every post in triplicate on the three Forums I regularly support.... I have thousands of photos, and over 10,000 links to those photos, every single one of which I would have to find, and then change, one at a time, to point the image in the thread to the new web location.... Obviously, that would take me years of work, since I have been doing this now for a decade.... so it's simply not practical.... It would be a huge chore with no reward, IMO....
In addition, other hosting services, such as Imgur, have language in their Terms of Service that allow them to do the same thing Photobucket just did, or even worse, to delete all your images, your account, and prevent all links to the website you linked to, not only by you but by others.... and they are the only ones to decide if and when to do that.... Why would I spend a year of my life moving and relinking all my work.... just to possibly have it disappear again?.... I'm too old to take on such a monumental (and thankless) project.... when I can keep the status quo for $100/yr (I have been paying $30-$50/yr. for a long time already).... I couldn't afford their initial $400/yr. "ransom".... but they came (partially) to their senses.... so I'm staying where I am....
I don't like it.... but the alternative is to let a decade of work disappear....
Bob
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Gotcha ;)
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"Incidently, the best .22LR target (subsonic) ammo has an ES of 2.5-3% over a box of 50"
Hey Mr. Bob care to share that brand name with us? :)
Thanks
Ray
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Eley Tenex, can't remember the lot number.... http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/velocity_dispersion.htm (http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/velocity_dispersion.htm)
The theoretical vertical dispersion at 50 metres for the .22LR standard projectile is then 1mm for every 3.9 ft/sec. change in muzzle velocity.
Also you may find this article interesting.... http://carteach0.blogspot.ca/2010/12/testing-22-rim-fire-ammunition-for.html (http://carteach0.blogspot.ca/2010/12/testing-22-rim-fire-ammunition-for.html)
Bob
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I did not know that! Thanks for sharing this info, great stuff!
+1
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All this talk about subsonic .22 ammo reminds me of one of the reasons I originally got into airguns. I wanted something quiet and safe for the shooting situation I had, and tried to make the subsonics work in that environment.... unsuccessfully. I ended up buying a cheap Chinese .22 underlever. One of the first shots I took with it nailed a squirrel with a lucky hit at close range, and that was all it took to get me hooked. I don't think I ever hit anything else with that gun, but it was a game changer for me.
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and now our more powerful PCPs are louder than any .22 subsonic by a wide margin.... ::) .... at least in Canada they sure are.... :'(
Bob
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This is neat, great info! I have never heard of any of it. Is there a place to by the software to do this?
Thanks Bill C!
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If you are looking for the ChairGun program, you can download it here.... https://www.hawkeoptics.com/chairgun.html (https://www.hawkeoptics.com/chairgun.html)
Bob
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If you are looking for the ChairGun program, you can download it here.... https://www.hawkeoptics.com/chairgun.html (https://www.hawkeoptics.com/chairgun.html)
Bob
Thanks Bob!
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Currently I post virtually every post in triplicate on the three Forums I regularly support.... I have thousands of photos, and over 10,000 links to those photos. Bob
This kind of dedication to serve and to advance the science & joy of our hobby — wow, THANK YOU, BOB!
I just recently read through a bunch of posts on the Bob and Lloyds Workshop forum, and I found many gems! :D
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For springers, is there a typical path the muzzle does after you pull the trigger?
After zeroing the scope with a certain pellet, I'm trying to figure why for some heavier/slower pellets the groupings are also to the side (besides the expected downwards).
Maybe, it (path) would also explain that ES would cause some effect to the side, besides the vertical stringing?
Just thinking, maybe we could attach a laser device to the barrel and record the laser dot with a camera to see it moving in slow motion? Unfortunately, I don't have the camera.. Maybe, someone already did that?