Strelok app giving me weird readings with my .22 - What's wrong?

[gunsrfun1]

I've just started using the Strelok app, and I compared its readings to my "real-world" settings, and I am getting strange results. So I am hoping someone can tell me what the problem (with the app, I presume) is.

Here is some basic info, and screenshots:
1) CZ 452 with a Burris Fullfield E1 4.5 - 14x42 scope, 1/4 MOA clicks windage and elevation
2) It is mounted with Burris signature rings, using +/-20 MOA inserts, giving me ~ 25 MOA of downward cant (based on the Burris table that factors in distance between the rings)
3) Wolf Match Target 40 grain, 1050 fps
4) Zeroed at 25 yards

Now on to the screenshots. First is my actual results and settings for the scope, shooting from 25 yards to 200 yards. Note the number of clicks from my 25-yard zero for POA/POI at 50, 100, and 200 yards (14 up, 40 up, and 112 up).


Now take a look at my inputs to Strelok for the scope and the cartridge. (I got the BC from a post on another forum):


Now here is where we start getting hinky. See the three screenshots below with the Strelok recommended click adjustments for 50, 100, and 200 yards. The Strelok recommendations for 50 and 100 are way off from my actual adjustments (3.5 vs. 14, and 33 vs. 40), but the recommendation for 200 yards is basically the same as my actual adjustment (111 vs. 112).



So I am confused, and I don't know how reliable this will be for other yardages.

Am I doing something wrong? Is the -20 MOA cant throwing the app off? Something else?

Thanks

 

[mcb]

Your ballistic coefficient looks low for a 40gr 22LR (typically 1.3-1.7 G1). Is the velocity your using the velocity off the box or the velocity you measured from you gun. It really needs to be the velocity from your gun.

 

[gunsrfun1]

It's the velocity from the box. I have no way to measure from the gun.

As to the BC, I changed it to 1.5 from .115 (average of your recommendations of 1.3 - 1.7) and it made it worse.

All the posts about the BC for this cartridge are pegging it at somewhere from .100 - .130 or so. (Wolf doesn't give it out.)

 

[mcb]

It's the velocity from the box. I have no way to measure from the gun.

As to the BC, I changed it to 1.5 from .115 (average of your recommendations of 1.3 - 1.7) and it made it worse.

You really need the actual velocity from your gun that is likely the biggest source of error. Your gun could be 50+ fps different than the box and at those ranges that is going to make a big difference.

 

[mcb]

There is a trajectory validation in Strelok (look in the documentation). Playing with that I found that using a BC of 1.3 and a velocity of 951 fps matches you 100 yard and 200 yard adjustments off you 25 yard zero but is way off you 50 yard adjustment. With 22lr shooting out to 200 yards I think you might be better off with 50 yard zero.

 

[gunsrfun1]

Thanks, that does help. Two questions:

1) What is a "call trajectory validation?"
2) For now, I am going to stick to the 25 yard zero (no time to re-zero and then re-shoot). So ... is there a particular subset of range of yardages between 25 and 200 where, using your numbers for MV and BC, I am more likely to be "close" using Strelok when trying to get a reading? For example, will I be more likely to be "close" (Strelock vs. reality) at shorter ranges, or at longer ranges? (But never more than 200).

PS - Generally speaking, how accurate is Strelok anyway? Just curious, since this is my first time using it.

Thanks again.

 

[mcb]

Thanks, that does help. Two questions:

1) What is a "call trajectory validation?"
2) For now, I am going to stick to the 25 yard zero (no time to re-zero and then re-shoot). So ... is there a particular subset of range of yardages between 25 and 200 where, using your numbers for MV and BC, I am more likely to be "close" using Strelok when trying to get a reading? For example, will I be more likely to be "close" (Strelock vs. reality) at shorter ranges, or at longer ranges? (But never more than 200).

PS - Generally speaking, how accurate is Strelok anyway? Just curious, since this is my first time using it.

Thanks again.

That was a typo on my part. The function in the Strelok program is called [trajectory validation]. Look up how to use it in the documentation for Strelok. It will let you enter your real world results at a particular range and let you adjust the velocity or ballistic coefficient to match those results.

The longer range your zero is the better the prediction usually are within reason.

I have found that with a good measured muzzle velocity and using the trajectory validation to tweak the BC I got very good results with my 10/22 for use in NRL22 competition.

This target was shot at 50 yards (zero), 75 yard, 100 yards, 125 yard, and 150 yards and when I measure the drop to the center of each group it was within an inch or better to what Strelok predicted.

 

[Walkalong]

The .22 LR is hard to get right in a ballistic program, you'll need to tweak velocity and BC. I chronoed the rounds to get muzzle velocity and still had to change the FPS to get the curve close (+/- a tenth out to 300). I actually chronoed the rounds at distance as well. If I trued BC at 300 it didn't work up close, if I trued BC up close, it didn't work out past 150ish.

With Center X that gave me 1105 FPS at the muzzle I ended up using 1114 FPS and a G7 BC of .062.

This is data I got at the range a couple of days before an NRL-22 match at Altus. After tweaking the FPS and BC to get the curve to match very closely the program had me on target all day. It was a very frustrating journey that started in Strelok and ended up in my Kestrel (Either works).
Work gave me a new phone and I lost Strelok etc.

Oh, and I zero at 50 yards.

 

[gunsrfun1]

Thanks. I have the free version of Strelok, and unless I am missing something, I don't think the free version offers trajectory validation. So I may just upgrade.

That was a typo on my part. The function in the Strelok program is called [trajectory validation]. Look up how to use it in the documentation for Strelok. It will let you enter your real world results at a particular range and let you adjust the velocity or ballistic coefficient to match those results.

The longer range your zero is the better the prediction usually are within reason.

I have found that with a good measured muzzle velocity and using the trajectory validation to tweak the BC I got very good results with my 10/22 for use in NRL22 competition.

This target was shot at 50 yards (zero), 75 yard, 100 yards, 125 yard, and 150 yards and when I measure the drop to the center of each group it was within an inch or better to what Strelok predicted.

 

[Varminterror]

It seems we generally need a couple of profiles (multi-BC) to get 22LR out past 300yrds. But you should be closer than what you’re seeing.

In general, close range errors are first caused by scope height error, then by velocity. Downrange errors are usually BC. Of course, what defines close range for centerfire doesn’t apply for downrange for Rimfire, so deciding which is which is tough.

So… playing with StrelokPro this morning, the ONLY way I can get close to your actual trajectory is by using an optic height below 1”. Somewhere between near .75” optic height gives me a trajectory very close to what your real world data describes - however, I’ll assume your scope isn’t actually, even possibly only sitting 3/4” above the bore.

 

[gunsrfun1]

Thanks Varminterror, you are right, scope height is not that low. But changing it to .75" in the calculator does bring the 50, 100, and 200 recommendations roughly in line with my real-world findings. So, who knows what is going on. I am wondering if using the Burris ring inserts that are giving me the 25 MOA built-in downward cant is somehow throwing the calculator off. But I don't see how that would have an impact. Or would it?

I did read somewhere that the Strelok Pro version is more accurate; plus it contains the Trajectory Validation feature mentioned in a post above. (The free app does not, as far as I can tell.) So I am going to order the Pro version and play around with it a bit more.

The good news is that my scope has holdover lines on the vertical reticle, so I can always try some Kentucky windage (and elevation) if need be, and hope that works.

Thanks again everyone.

 

[denton]

I couldn't get acceptable results from Strelok and deleted it.

 

[mcb]

I couldn't get acceptable results from Strelok and deleted it.

How is this helpful? Many of us have used Strelok with rimfire and center-fire very successfully. I have ten different guns in my copy. Rimfire, subsonic, and center-fire, and used it out to 1000 yards and I suspect others here have more guns and used it to greater ranges than I have with equal success. It's probably in the top five of the best ballistic mobile apps going. It is a well made, well supported, and capable tool, but one with a moderately steep leaning curve. Threads like this are to help people up that curve.

 

[denton]

How is this helpful? Many of us have used Strelok with rimfire and center-fire very successfully. I have ten different guns in my copy. Rimfire, subsonic, and center-fire, and used it out to 1000 yards and I suspect others here have more guns and used it to greater ranges than I have with equal success. It's probably in the top five of the best ballistic mobile apps going. It is a well made, well supported, and capable tool, but one with a moderately steep leaning curve. Threads like this are to help people up that curve.

One possibility for the cause of the OP's problems is that the software isn't really that good, and no amount of tinkering is going to fix it. OTOH, if you are getting good results, maybe it is OK.

It has been a few years since I deleted my copy, and I don't even remember the details of why I did that. I just remember that I concluded it wasn't salvageable.

I do recall that I didn't have any difficulty learning to use it. It just didn't give me useful results.

 

[Varminterror]

I am wondering if using the Burris ring inserts that are giving me the 25 MOA built-in downward cant is somehow throwing the calculator off. But I don't see how that would have an impact. Or would it?

No, it’s certainly not that. I have 20-40moa correction on most of my rifles and pistols, and do not have any issues. The angled bases and/or rings don’t influence the trajectory, and only influence where you end up from optical center (aka, how much ballistic range you can access with your available adjustment range).

 

[Varminterror]

One possibility for the cause of the OP's problems is that the software isn't really that good, and no amount of tinkering is going to fix it.

There are thousands of shooters using StrelokPro to shoot distances well beyond 1,000, and many at distances measured in miles. The “multi-BC” function of these calculators is a little more difficult in StrelokPro than in some other applications - but in many cases, when we get that far out where custom curves and bullet profiles become not only relevant, but necessary, we end up using multiple profiles for various spans of bullet flight anyway.

Bugs do happen, and Igor is great about supporting through his Facebook user group. Might be worth posting this issue there as well.

 

[mcb]

One possibility for the cause of the OP's problems is that the software isn't really that good, and no amount of tinkering is going to fix it. OTOH, if you are getting good results, maybe it is OK.

It has been a few years since I deleted my copy, and I don't even remember the details of why I did that. I just remember that I concluded it wasn't salvageable.

I do recall that I didn't have any difficulty learning to use it. It just didn't give me useful results.

Maybe it was more difficult then you remember and that is why you results were less than useful? I have found it a wonderful program for the price and have used it successfully many times. Two notables:

I took my new 6mm Creedmoor chassis gun and a properly setup Strelok to my first Guardian long range match. I got first round hits out to 1000 yards on targets in the 2 MOA to 3MOA size with that program having never shot the rifle beyond 200 yard prior to that match. I finished 15th of 60 competitors

My first NRL22 match I shot using a 10/22 and a 35 year old Tasco 3-9x32 scope with a simple duplex reticule and a heap of help from Strelok, again setup properly. The use of Strelok's reticle preview and ability to put specific size targets at specific into the image was critical to getting my holds right with only the crosshair and duplex point for my holds, since with that scope dialing for range was not a realistic option. We shot targets from 25 to nearly 200 yards, I finished 2nd of a bit over 20 competitor.

If you look at surveys of what ballistic programs people are using for PRS, NRL, NRL22 and similar competitions then is usually third or fourth behind dedicated hardware like Kestrels with Applied Ballistics and mobile programs like Geoballistics and Applied Ballistics Mobile. For the price (free if you want, pro is $11.99 compared to nearly three times that for Applied Ballistics Mobile) you can do a lot with this program. Igor Borisov the person that wrote and maintains the software is extraordinarily responsive to his customers adding scope/reticules nearly on request, fixing minor bugs that are reported, and taking feed back from his customers to improve the program.

Constructive criticism of Strelok or even suggestions to other better solutions would have been helpful. Your response was not... Be helpful!

 

[Walkalong]

The “multi-BC” function

The first time I shot .22 LR to 300 yards after getting muzzle velocity and then tried to make the data match my first thought was it's almost like it needs two BCs, one to yardage X and another to yardage Y.

I tried G4 I think it was suggested for .22 LR, but it didn't help. I ended up with G7, but I think Jeff is using G4, maybe G1, but I'm guessing, don't remember for sure.

At any rate, just play with it until you get it real close.

The two best things I ever did to improve ballistic data for 6 Dasher in PRS was to true BC at distance and let the Kestrel calculate muzzle velocity as weather changed. Strelok is good, but the Kestrel is a big step up IMHO. Just getting the Kestel improved things, but getting more than one muzzle velocity at different temps, inputting them into the Applied Ballistics program in the Kestrel and then letting it calculate MV was big.

 

[gunsrfun1]

No idea what you mean by G4, G7, G1. What do they mean?

 

[gunsrfun1]

Just bought the Strelok Pro version, I'll see how that works out.

 

[Walkalong]

https://www.snipershide.com/shooting/threads/strelok-users-actual-22lr-bullet-bc.6949401/

G1, G2, etc are different drag functions. You picked one in your Strelok ballistic solver.

I'm using G7, I believe my buddy is using G1,

 

[mcb]

No idea what you mean by G4, G7, G1. What do they mean?

G1, G4, G7 and several others are drag models (G1 and G7 are the most common in use today). The coefficient of drag for a bullet (or nearly anything moving through a fluid) changes depending velocity. Thankfully they found that this velocity dependent drag function for bullets in air was fairly scalable. So if you had a particular shape of bullet and you scaled it bigger or smaller this drag function kept its general trend/shape across the velocity range and was simply scaled up or down inversely proportion to the size.

ie a bullet with a G1 ballistic coefficient of 1.0 will have half the drag coefficient value as a bullet with a G1 ballistic coefficient of 0.5 at a particular velocity.


This is the shape of the G1 and G7 bullet. You'll notice the caliber is not specified and all other dimension are based on that unspecified caliber.

These G models work really well with some bullets but with other bullets, for example the real long skinny very low drag bullets being used by longer range shooters the old G models are not accurate enough especially as ranges get long. Rather than create a new drag model some manufactures are simply using multiple BC's for various sub-ranges of velocity and the program smooths this into a usable semi-custom coefficient of drag function. (Strelok can do this)

ie the 230gr Sierra Matchking use a G1 of .800 @1880 fps and above .780 between 1600 and 1880 fps .740 @ 1600 and below


The above is the generic (BC = 1) coefficient of drag (Cd) as a function of velocity for the G1 and G7 models. The velocity across the bottom of graph is in Mach (speed of sound)

I believe Applied Ballistic has gotten rid of the the G functions for bullets that are in their programs library. They have taken the time to shoot a huge variety of bullets and track them with radars and create velocity dependent drag models for each individual bullet and dispense with trying to fit/scale a generic G-models to bullet that they don't fit well to.

-rambling

 

[Varminterror]

Yeah - for 22LR, I’ve played with different tricks, but I end up just using G1’s, truing as close as I can get, using multi-BC occasionally, but more frequently using multiple profiles for different range segments - but for 0-300 with 22LR, my waterline is way less of a problem than ammo, so I usually just use one profile with true velocity and trued BC.

I do find a proper DOPE table as reference - a double check opportunity - for 22LR 0-300 is much more pertinent than for centerfires.