If we need to test and make our own trajectory chart why use Strelok?

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Jshepherd70

Member
Dec 3, 2019
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OH, United States
I have been beating my head against the wall trying to get all of the numbers to match, looking into multi B.C etc. It kinda just hit me that if really all I do is 100 yards are less. why am I even using strelok?

At the end of the day if 30y=0,50y=7,75y=24,100y=45 Why would I even need the app? Is it just to get you close for long range or for wind? 

I found it to be fairly close until I went to the .25 hades and for me it is way off for those. About 13 clicks off at 100y actually 75y is off by 11. I have to use an abnormally high B.C number to have it make sense (.050)

I am not knocking strelok at all as it may be user error or not understanding how to really use it well, I am just trying to grasp the Why.
 
I use iStrelok because I often shoots pest birds high on roofs and silos and you need to adjust for this angle. iStrelok will determine the angle and tell you the calculated drop using it. Same for if you have any wind and you need to adjust.



It works. I popped a starling at 81 yards yesterday with my .22 Compatto using the adjustment iStrelok provided. Nice loud pop when the pellet hit home and a plume of feathers...
 
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You don't have to use a calculator like Strelok, it is just a tool that helps if the range is random or to give you a better idea of what your trajectory is at any point.

But the old saying applies, "garbage in = garbage out". Few published BC are very precise, it's just a ballpark figure to get you close. You have to shoot to get some data that can then be plugged into Strelok to get YOUR BC at your velocities with your projectile. Strelok has a page for that.

Then using that, you can use it for any range entered and get very precise shot placement.

I use a calculator (Strelok or Chairgun) to make a dope card or a tape that I put on the gun for quick reference. It would be a LOT harder to make it if I had to shoot at dozens of ranges to find out the adjustment clicks needed for those ranges. With something like Strelok I just shoot at two ranges and find the BC that matches.

Note that most people use the G1 profile but really the GL or RA4 drag profile gives me better results with the stubby/short, fairly blunt nosed bullets air rifle shoot. That accounts for a lot of people's trajectory mismatch. [ Use GA drag profile for pellets!!! Or you'll get that GIGO ]
 
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You probably aren’t using it correctly, maybe selected a wrong option or input wrong data somewhere. Impossible for us to know unless you post every setting you input into the app. 


I’d bet the farm you entered something incorrectly and adjusting the pellet BC wont neutralize the mistake.
Click to expand...

When only changing just the cartridge I've ruled out the other settings but happy to share. I'll have to upload some screenshots.

It works fairly well ( within a few clicks) with my Impact .30 and also with my Crown with the JSB king 25.4 with the supplied B.C. of .036. They list the hades at .026 and maybe it is just that pellet being quirky.
 
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You don't have to use a calculator like Strelok, it is just a tool that helps if the range is random or to give you a better idea of what your trajectory is at any point.

But the old saying applies, "garbage in = garbage out". Few published BC are very precise, it's just a ballpark figure to get you close. You have to shoot to get some data that can then be plugged into Strelok to get YOUR BC at your velocities with your projectile. Strelok has a page for that.

Then using that, you can use it for any range entered and get very precise shot placement.

I use a calculator (Strelok or Chairgun) to make a dope card or a tape that I put on the gun for quick reference. It would be a LOT harder to make it if I had to shoot at dozens of ranges to find out the adjustment clicks needed for those ranges. With something like Strelok I just shoot at two ranges and find the BC that matches.

Note that most people use the G1 profile but really the GL or RA4 drag profile gives me better results with the stubby/short, fairly blunt nosed bullets air rifle shoot. That accounts for a lot of people's trajectory mismatch. [ Use GA drag profile for pellets!!! Or you'll get that GIGO ]
Click to expand...

This is good info. I have seen the other drag profiles but didn't put much thought into it as when I tried others it made about 1 click difference. I would also agree that initially it made things much quicker to get close but these hades through that out the window!

I have double and triple checked my zero distance which is 30 yards. That is my most common pesting area. I then check 50,75,100 and can interpolate from that.

What I did find out by experimenting was that at 925 fps the .25 king 25.4 track nearly identical to the hades at 890 fps. all the way to 100y 
 
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Are you measuring your scope height correctly? Is your scope listed in the strelok data base? Is it set to correct focal plane (zoom level if 2nd focal plane)? Is the MOA/MIL correct? Is the scope click values correct? Are you rezeroing when you switch to the hades pellets?
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Yes, I have double and triple checked these. This is an FFP Hawke sidewinder and my Impact .30 is a Hawke Frontier SFP. Both are .100 Mil . I am not using holdover either so that narrows the error down to a pellet that doesn't fly as linear as my other pellets. I absolutely zero at 30 yards on each pellet. I shot at least 2 mags in a row as that was my first thought and even at that it doesn't explain the error being so far off. I am going to try one more time with a B.C of .043 GA and try to trim it from there.

What I am getting at is the info is very close for one pellet but way off on the hades. If I have to redo everything then I may as well just use paper and pencil. If I am spending more time and effort making an app work then I just fail to see the point for my use.
 
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Shot a few hundred more rounds today. The hades shoot about 25-30 fps slower than the 25.4 kings but the trajectory to 75 yards is nearly identical. I then bumped up the hammer for the hades to shoot at 925-930fps to match the kings and it didn't affect it much. Basically, the Hades are not close to the B.C that strelok has listed or at least not for my crown 700mm.

One thing that had me a bit screwed up at first was using the FX chrono with their new mount hanging on the barrel affected POI by about an inch at 75 yards.
 
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Got a question/PM on how to change the Drag Function in Strelok

First screensho tap on the big center bar which lists the rifle, scope and bullet data

1577584145_21303910935e080611235a49.81918699_Strelok 1 Screenshot 2159.png


Second, again tap on the big bar where bullet info is listed

1577584161_7808795135e080621d17366.09217063_Strelok 2 Screenshot 2257.png


Third screen you will see in the middle of the page it says "Drag Function", tap on the bar

1577584174_14315227615e08062ea017a7.34221564_Strelok 3 Screenshot 2318.png


You will be seeing the various drag functions and can check the one you want then tap 'OK'

G1 is for a spitzer nose flat base equivalent to a 150gr .308 jacketed (Not really applicable to our projectiles)

G7 is a VLD BT spitzer (VLD Very Low Drag) [Very much NOT applicable to much of anything shot in airguns!}

RA4 is the .22LR bullet which matches a lot of pistol bullets and many airgun slugs (this one works well in many cases)

GA is Diabolo airgun pellets (self explanatory)

GL is a simi-spitzer / round nose profile and it too is sometimes a good match for pistol or airgun slugs

GS is round ball

GC is a wadcutter/cylinder some SWC pistol bullets follow/fit this drag function well

G8 is a little used VLD flat base




 
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One thing may help but is 'work' is "truing' by ballistic coefficient if needed" which is item 8 in the How to on the Strelok website.

(Wife: Don't you read the instructions, Dear?

Husband: Grumble Grumble Grumble)

http://www.borisov.mobi/StrelokPro/android/configuration.html

Also note that you might use since it is cold is that bullets slow down more in denser cold air and you can compensate for that in Strelok. Go to the third page (screenshot 3) and tap for "Bullet Speed" and fill in the data.

See this screenshot below with the temperature/velocity drop numbers. See that the relationship is constant: 25 FPS for every 18 F change. You just get an ACCURATE measurement of the temp RIGHT WHERE YOU ARE AT THE TIME then shoot across the chrony to get what your FPS is. Mine was 78F at the range that day/hour/min and I clocked 910 FPS and put that in the second row. So adding up, I got the 96 F day numbers and put them in the first row. Subtracting the 25 and 18 from my second line gave my third line and subtracting again gave me the fourth line. Since it rarely gets below 40F here I did not go lower. Strelok then uses this chart to calculate for whatever the temperature you enter is on the main page

1577586823_9056947425e08108791d585.65522349_Strelok 4 Screenshot 2509.png

 
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One other thing to check is a different MIL/MOA setting. I realize that Hawke and most other list it clearly on the top turret cap. That does not mean it's correct.

I have watched a few scope reviews from reputable powder burner reviewers that found the turrets way off at 400,600 and 800 meters. The clicks on those matched the MOA clicks exactly in several cases. Also try a lower BC for the Hades. I think I got around .023 for a Hades out of Chairgun.
 
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One other thing to check is a different MIL/MOA setting. I realize that Hawke and most other list it clearly on the top turret cap. That does not mean it's correct.

I have watched a few scope reviews from reputable powder burner reviewers that found the turrets way off at 400,600 and 800 meters. The clicks on those matched the MOA clicks exactly in several cases. Also try a lower BC for the Hades. I think I got around .023 for a Hades out of Chairgun.
Click to expand...

Thanks, I know it is input correctly but I have not actually tried to verify. The issue is that it does work well for every other pellet I try except for the hades. I've just given up trying to make sense of it and use the 25.39 king b.c. which is .038 ( GA) If I use .02x it is around 14 clicks off at 100. 
 
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