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500 Yard Dope with SK Standard Plus and Strelok Pro

N

Norman1950

Private
Minuteman
Jun 3, 2020
66
49
Meridian, ID
I am shooting a CZ457 Varmint barreled action in a Indian Creek Designs chassis with Luth MBA-3 stock and a Arken 6-24x50 SH4 MIL on top of 30 MOA Area 419 base.

I am zeroed at 50 yards with excellent groups (under 1/2"). My average speed is 1073 with low SDs with SK Standard plus. Strelok has been pretty accurate on the calculations under 100 yards for NRL22 competitions.

Weather conditions: Wind about 4.5 mph coming from 10:00, 84° F = DA of 4680

Strelok 100 yards calculation is 1.8 mils, which matches my results.

Strelok 300 yards calculation is 13.3 mils, and I was at 13.5 mils hitting a 12"x12" plate with 1.5 mils left for wind.

Strelok 500 yards calculation is 28.5 mils, and I had to put the turret to 24 mils, and hold over 12 mils, a total of 36 mils and 4 mils left hold. I was able to get hits on a 24"x24" plate.

Why is my DOPE way off on 500 yards? Do I need to adjust my BC?

I am still fairly new to trying to run out calculations on Strelok and figuring out BC, or a custom 22LR curve.

Thank you for inputs.
 
BC is based on velocity, and as things get slower, BC gets lower. They say at 350 yards, your BC is around .11. At 50 yards the BC is .172.

With a simple thing like Strelok, I've generally used like .135 to get pretty close results for everything from 50-250 yards.

To get a perfect curve you basically need a custom curve with BC per velocity range.
 
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I just pulled up Stelok for my 457, shooting SK Pistol Match at 1,068ft/s, it calls for 29.1. I’ve never shot that far - only out to 300, and it was dialed in pretty well.

Maybe try adjusting the drag function to Lapua Center X. My buddy said that has the ability to adjust for changes in BC
 
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Do I need to adjust my BC?
Click to expand...
I ended up being Ok with the .135 number mentioned above for shots on 3moa target to 200-300.

After that, keep in mind 22LR also becoming sketch at some stage for almost everyone :ROFLMAO:
 
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Strelok Pro has a 3-tiered truing function which might help here. Instead of tapping the Truing button at the lower right of the home screen, touch and hold it for a couple seconds. Then you have the option to enter actual elevations observed at three different ranges. I would choose the BC tab for rimfire rather than the default speed tab.

Full disclosure: I have not used this function. With Center-X and the .22LR Lapua Center X 2.59g drag function, Strelok Pro gives me correct elevation/windage settings out to 400 yards. I might tinker with it just to see...
 
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ma smith said:
I ended up being Ok with the .135 number mentioned above for shots on 3moa target to 200-300.

After that, keep in mind 22LR also becoming sketch at some stage for almost everyone :ROFLMAO:
Click to expand...
Thank you for your input.

200-300 yards I was on. Thinking back, I need to also check to see how much, if any, elevation to the 500 target. I don't have a rangefinder at the moment, need to borrow my friend's RF again.
 
DownhillFromHere said:
Strelok Pro has a 3-tiered truing function which might help here. Instead of tapping the Truing button at the lower right of the home screen, touch and hold it for a couple seconds. Then you have the option to enter actual elevations observed at three different ranges. I would choose the BC tab for rimfire rather than the default speed tab.

Full disclosure: I have not used this function. With Center-X and the .22LR Lapua Center X 2.59g drag function, Strelok Pro gives me correct elevation/windage settings out to 400 yards. I might tinker with it just to see...
Click to expand...
Thanks, I didn’t know about that. My dope is good with strelok but this feature might be the missing link.
 
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DownhillFromHere said:
Strelok Pro has a 3-tiered truing function which might help here. Instead of tapping the Truing button at the lower right of the home screen, touch and hold it for a couple seconds. Then you have the option to enter actual elevations observed at three different ranges. I would choose the BC tab for rimfire rather than the default speed tab.

Full disclosure: I have not used this function. With Center-X and the .22LR Lapua Center X 2.59g drag function, Strelok Pro gives me correct elevation/windage settings out to 400 yards. I might tinker with it just to see...
Click to expand...
Thanks for this info! Did not know about that either in Strelok. I will have to play with it. For BC I am using .132.

Thanks again.
 
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I adjusted BC at 200 & 300 yards prior to that my DOPE was always to high now it appears to be good
 
The three tiered truing option in Strelok is simply going to average the results you put in. It will NOT create a custom muti bc curve for you.
 
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Norman1950 said:
I am shooting a CZ457 Varmint barreled action in a Indian Creek Designs chassis with Luth MBA-3 stock and a Arken 6-24x50 SH4 MIL on top of 30 MOA Area 419 base.

I am zeroed at 50 yards with excellent groups (under 1/2"). My average speed is 1073 with low SDs with SK Standard plus. Strelok has been pretty accurate on the calculations under 100 yards for NRL22 competitions.

Weather conditions: Wind about 4.5 mph coming from 10:00, 84° F = DA of 4680

Strelok 100 yards calculation is 1.8 mils, which matches my results.

Strelok 300 yards calculation is 13.3 mils, and I was at 13.5 mils hitting a 12"x12" plate with 1.5 mils left for wind.

Strelok 500 yards calculation is 28.5 mils, and I had to put the turret to 24 mils, and hold over 12 mils, a total of 36 mils and 4 mils left hold. I was able to get hits on a 24"x24" plate.

Why is my DOPE way off on 500 yards? Do I need to adjust my BC?

I am still fairly new to trying to run out calculations on Strelok and figuring out BC, or a custom 22LR curve.

Thank you for inputs.
Click to expand...
Some thing to keep in mind is that your group size at 500 is probably 3'+ in the vertical so shooting at a 24" plate you may have been hitting with the bottom of your group but center was above the plate.

When trueing at long range with huge group sizes you will need a very large plate to have any hope of being close to accurate.

With Strelok I have found with most ammo if you true your BC at 400 yards using actual velocity you will be good at 500.

When truing your data you must account for ALL environmental factors very carefully and accurately or it will not work. This is very evident with 22lr.

Also if your using Strelok I have found using RA4 instead of G1 to be more precise with most ammo particularly at the longer ranges.
 
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CRPS Shooter said:
The three tiered truing option in Strelok is simply going to average the results you put in. It will NOT create a custom muti bc curve for you.
Click to expand...
True. I would think the better option would be to use the truing option to get both your BC and MV at a certain ranges and then punch that info into the MulitBC table to get a better curve? Full disclosure I am probably wrong! :LOL:
 
nikonNUT said:
True. I would think the better option would be to use the truing option to get both your BC and MV at a certain ranges and then punch that info into the MulitBC table to get a better curve? Full disclosure I am probably wrong! :LOL:
Click to expand...
Yes that works. Its not quite that simple because your still referencing a drag model and you can not create a sudden drag coefficient change with out messing things up but it works well for the small changes.
 
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CRPS Shooter said:
Some thing to keep in mind is that your group size at 500 is probably 3'+ in the vertical so shooting at a 24" plate you may have been hitting with the bottom of your group but center was above the plate.

When trueing at long range with huge group sizes you will need a very large plate to have any hope of being close to accurate.

With Strelok I have found with most ammo if you true your BC at 400 yards using actual velocity you will be good at 500.

When truing your data you must account for ALL environmental factors very carefully and accurately or it will not work. This is very evident with 22lr.

Also if your using Strelok I have found using RA4 instead of G1 to be more precise with most ammo particularly at the longer ranges.
Click to expand...
Thank you for your advice. I know I still have a lot to learn in the aspects of BC, curves, velocities at certain distances. I have been using the Magneto Speed Sporter for my velocities. Per the picture, I have it mounted to the Arca rail of the chassis so it will not influence the barrel harmonics. I only have it one the gun when I am testing/verifying velocities, and was not used during this shoot.

I am shooting at a members only range, and can only shoot the steel they have hung up at the certain distances. We have a 300 yard "pit" and jumps to the 500 yard "pit".

I am not familiar with RA4, I will need to do more research.

Thanks again for your help.

20210506_200737.jpg
 
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I prefer G1 to R4.

I had the chance to verify multiple distances from 50 to well over 300. I then compared my actual DOPE to several different ballistics profiles in Strelok pro. G1 was nearly perfect so I run G1. I've used the Truing feature as well with good results when I'm unable to get a chronograph on a new lot.

Personally, I think it's imperative to start at a known number and why I prefer to chronograph all my ammo. Usually very easy w/ the Magnetospeed and a similar setup to what you have above.
 
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As Jeff noted his case G1 is best. It is ammo dependent you will have to test for yourself. Also if you true at 300 or 400 you may find things different as well.
 
Norman1950 said:
I am shooting a CZ457 Varmint barreled action in a Indian Creek Designs chassis with Luth MBA-3 stock and a Arken 6-24x50 SH4 MIL on top of 30 MOA Area 419 base.

I am zeroed at 50 yards with excellent groups (under 1/2"). My average speed is 1073 with low SDs with SK Standard plus. Strelok has been pretty accurate on the calculations under 100 yards for NRL22 competitions.

Weather conditions: Wind about 4.5 mph coming from 10:00, 84° F = DA of 4680

Strelok 100 yards calculation is 1.8 mils, which matches my results.

Strelok 300 yards calculation is 13.3 mils, and I was at 13.5 mils hitting a 12"x12" plate with 1.5 mils left for wind.

Strelok 500 yards calculation is 28.5 mils, and I had to put the turret to 24 mils, and hold over 12 mils, a total of 36 mils and 4 mils left hold. I was able to get hits on a 24"x24" plate.

Why is my DOPE way off on 500 yards? Do I need to adjust my BC?

I am still fairly new to trying to run out calculations on Strelok and figuring out BC, or a custom 22LR curve.

Thank you for inputs.
Click to expand...
This is good info. My Sk std + is an avg 1073 out of my Bergara. I just bought a Kestrel with BA and the BC for 3 loads they have are .114, .120 and .121. Two were vudoo profiles. I also did a profile with .172. None of the dope at 300 yds is under the 14 mil. But it’s new and I have yet to try it. So youre at 13.5 mil would have me inputting higher BC than the .172. My 100 yd is 1.9 mil. Crazy so much difference since I’m guessing the CZ is 1:16 twist. And velocity is dead on.
 
littlepod said:
BC is based on velocity, and as things get slower, BC gets lower. They say at 350 yards, your BC is around .11. At 50 yards the BC is .172.

With a simple thing like Strelok, I've generally used like .135 to get pretty close results for everything from 50-250 yards.

To get a perfect curve you basically need a custom curve with BC per velocity range.
Click to expand...
Based on your post would you have two profiles. One with a BC of .135 for 50-250 and then a profile for 250+ yds with a BC .110? This would help me instead of trying to have one profile with one BC that may work better for some distances than others.
 
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As mentioned earlier if you do a long press on the truing button in Strelok you get the new method with 3 entries. If your closer dope is matching the predictions set your first entry at 250 yards to preserve those results, use the other two entries at whatever longer distances you can properly measure the actual drop. It is basically a more limited take on DSF.
 
Bgriff008 said:
Based on your post would you have two profiles. One with a BC of .135 for 50-250 and then a profile for 250+ yds with a BC .110? This would help me instead of trying to have one profile with one BC that may work better for some distances than others.
Click to expand...
I switched to a kestrel custom curve so I don't know what I would do in practice using another app, but most likely I'd do something like that.
 
littlepod said:
I switched to a kestrel custom curve so I don't know what I would do in practice using another app, but most likely I'd do something like that.
Click to expand...
I recently picked up the Kestrel with BA. But have yet to use it. It had several profiles to pick from for SK std +.. it will be a trial and error but hoping it’s darn close.
 
If you got the Elite it also has the DSF function.
 
Bgriff008 said:
Based on your post would you have two profiles. One with a BC of .135 for 50-250 and then a profile for 250+ yds with a BC .110? This would help me instead of trying to have one profile with one BC that may work better for some distances than others.
Click to expand...
1 bc will easy get you past 400 if you use the bc profile that best matches your drop. You wont be perfect at 100 but within a 0.1 mil
 
6.5SH said:
Here you go:

www.snipershide.com

DSF truing with 22 Rimfire

Has anyone done it on the Kestrel? Ranges used? How well does it work
www.snipershide.com www.snipershide.com
Click to expand...
Yea I’ve read this so many times. I need to get to the range and give this a run. But again was a little confused just messing with the DSF function at home. It has to be my error and being unfamiliar with the functionality of the kestrel. Eventually I will learn it. Thanks for the help.
 
DownhillFromHere said:
Strelok Pro has a 3-tiered truing function which might help here. Instead of tapping the Truing button at the lower right of the home screen, touch and hold it for a couple seconds. Then you have the option to enter actual elevations observed at three different ranges. I would choose the BC tab for rimfire rather than the default speed tab.

Full disclosure: I have not used this function. With Center-X and the .22LR Lapua Center X 2.59g drag function, Strelok Pro gives me correct elevation/windage settings out to 400 yards. I might tinker with it just to see...
Click to expand...
I can't my Pro version to do that on Android.
 
Bgriff008 said:
So when shooting and impacting below a target do you input in DSF the amount of mil’s you suspect you are low until you get on target?
Click to expand...
Correct. Ideally you'd be able to see a dust splash and use the reticle to measure it (Ex. you had dialed a portion (20 Mil) and were holding on the 5 Mil line and saw dust splash at the 8 Mil line. Your observed impact for that yardage would 28 Mil.)
 
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I see that now but Google Play had no option to update. I'm on Android V10. I sent Igor a message to see what is the deal.
 
Bgriff008 said:
Yea I don’t quite know how to work the DSF function and whether I’m doing it correctly. I def need to be shown.
Click to expand...
I am using the kestrel 5700 elite also, honestly, just pick the custom drag model for the round you are shooting, zero it at the distance you choose and get a good Muzzle velocity calibration at 100yards and shoot it.

The data I am getting out of mine has been pretty spot on out to 300yards so far. Unfortunately I haven’t had the need or location to take it out any further yet.
 
Bgriff008 said:
Based on your post would you have two profiles. One with a BC of .135 for 50-250 and then a profile for 250+ yds with a BC .110? This would help me instead of trying to have one profile with one BC that may work better for some distances than others.
Click to expand...
Truing the muzzle velocity is going to be more important than the bc for subsonic rounds.

I listened to/watched a podcast with Bryan Litz and he touched on a few rimfire topics, this is one thing he mentioned.
 
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6.5SH said:
You are out of date, 6.1.3 is current, it is a newer feature.
Click to expand...
Something got fucked in Google Play. I ended up having to uninstall it then it wanted me to pay again. After that, it updated to the current version. Fucking bullshit.
 
It's Google Play and not Igor. He has no control over it. Anyway, I have the current functions now.
 
I know this is an old thread. I just joined here and was snooping around trying to learn things and found this. Wow! there is a LOT of great info here. I especially had been wondering if it was possible to use more than one distance for truing and here was the answer. Thanks to all the posters here.
 
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