Kestral 5700 Elite - Cal MV and Cal DSF

[sled_mack]

I am planning on going through these procedures tomorrow. I'm not sure how close I can get targets to the recommended ranges from the Kestral. For a .223 it wants a target at 632 yards. I'm not sure I can get a target past 500 and under 750 based on the range layout. Will 500 work?
Similar with DSF - Kestral wants 980 yards. I'm not even sure that is practical with a .223 out of an AR? Realistically, I can probably get 800 yards. Close enough?
I know the Kestrel site says that going too short will give invalid calibrations. Does invalid = bad, or does invalid = not optimum but better than nothing?

Lastly - these values are not available on the phone app for the Kestrel where you store gun profiles. So if I backup the profile to my phone, are these calibrations lost? Or are they stored and just not visible in the phone app?

It's fun learning all of this technology, but it is a bit of a challenge keeping up! So much for printing out drop tables based on DA and heading out to the range/match.

 

[_Windrider_]

Do you have access to a chrono?

 

[sled_mack]

I've got a labradar.

I plan to shoot over the chrono and see if this is even necessary. But if my data is off, these steps seem like the next logical thing to do. No?

 

[_Windrider_]

Nope. That stuff is for people who don’t know their MV. Read this thread and let me know if you have any questions.

https://www.snipershide.com/shootin...nd-frank-are-back.6891601/page-2#post-7170296

More than likely your BC is off because your velocity is different than published. Read this and I suggest truing your BC with your known velocity at around 3-400 with a 223. Then you should be gtg.

 

[Diver160651]

Nope. That stuff is for people who don’t know their MV. Read this thread and let me know if you have any questions.

https://www.snipershide.com/shootin...nd-frank-are-back.6891601/page-2#post-7170296

More than likely your BC is off because your velocity is different than published. Read this and I suggest truing your BC with your known velocity at around 3-400 with a 223. Then you should be gtg.

Not sure I read this correctly. You are usually spot on, but 3-400 is to close to really tune the BC even with a 223.

He should be dead on at 300 with the velocity being correct. Pushing the BC tuning out to 600 with result in a better curve.

Even then, one needs to be careful with a 223 their not “tuning” in too much wind, if the day isn’t perfect.

Edited to add: if the LabRadar speeds are resulting in wrong drops at 300-400, confirm you distance perfectly as well as the scope tracking before making drastic velocity adjustments in AB

 

[_Windrider_]

Not sure I read this correctly. You are usually spot on, but 3-400 is to close to really tune the BC even with a 223.

He should be dead on at 300 with the velocity being correct. Pushing the BC tuning out to 600 with result in a better curve.

Even then, one needs to be careful with a 223 their not “tuning” in too much wind, if the day isn’t perfect

Ok. 600 then.

 

[Diver160651]

Ok. 600 then.

Just spit out my coffee.. thanks

 

[sled_mack]

Nope. That stuff is for people who don’t know their MV. Read this thread and let me know if you have any questions.

https://www.snipershide.com/shootin...nd-frank-are-back.6891601/page-2#post-7170296

More than likely your BC is off because your velocity is different than published. Read this and I suggest truing your BC with your known velocity at around 3-400 with a 223. Then you should be gtg.

Read through that. I'm not sure how it relates to this question (the discussion was focused on wind solutions) other than pointing out that BC is based on velocity? And I am likely running under the tested velocity for the bullet.

I'm using the AB CDM in the Kestrel, which means there is no tweaking that number. I thought the advantage to using that, was that it was "banded BC" at different velocities?

So... Just switch to a G1/G7 and forget the CDM? I haven't researched it lately, but the G1/G7 debate in the past seemed to come down to personal preference?

File this under the category "nothing is ever as easy as it sounds".

Just for testing - maybe I'll create 3 profiles of the same gun, CDM/G1/G7. Enter in the same MV that I get from the chrono tomorrow (this will be the hottest temps I've chrono'd). See what gives me the best initial data, and which requires the least tweaking, if any, to make it correct.

 

[sled_mack]

Forgot to add - I've had this scope for a few years now and have done the scope tracking tests at least 3 times. It has always been on closer than I can manage to measure - both shooting a tall target and clamping it down and running the turrets. So I think I am good there.

The driving factor for doing this is that I've missed a few shots at matches that I am sure I should have made. Most of them being 475 to 700 yards. I understand that match conditions aren't the best indication of accuracy/data/etc. So I joined a range that goes out further (home range only 300 yards) so that I can shoot in a more controlled setting. For all I know, I'll hit everything at distance tomorrow and not need to tweak anything. Which will prove that I missed the match shots based on time/position/pressure/whatever.

Thanks.

 

[Kobyashi72]

So long as you are within 10% of the recommended truing range you Should be good but don’t go beyond 20%

Are you shooting steel or paper?

 

[sled_mack]

I'll be shooting steel. I've got targets that get down to 1 MOA at those distances, start on the big ones and work down to the smallest. Seems like the easiest way to do it with no one along for spotting. And my spotter scope is not going to see holes in paper at that distance.

 

[_Windrider_]

that Whole thread discusses using the BC method for wind hold estimation. If your BC isn’t correct though for your velocity it won’t work. That’s why I suggested read the thread and true your BC with your velocity then go from there. I can honestly say the CDMs are just ok..........for elevation. But I don’t know anyone who has had good luck with the. And wind. But if your muzzle velocity is accurate then they should follow suit. Maybe a tweak to the stability factor is needed within the CDM.

 

[Kobyashi72]

I'll be shooting steel. I've got targets that get down to 1 MOA at those distances, start on the big ones and work down to the smallest. Seems like the easiest way to do it with no one along for spotting. And my spotter scope is not going to see holes in paper at that distance.

Gotcha. I was wondering how you were going to get an accurate Center of Group measurement to true off of because that's what you would use to compare the prediction between the CDM/G7/G1.

Check your azimuth of fire to the target with the compass app on your phone or an analog compass to sanity check the kestrel. You might have to recalibrate the kestrel.

Make note of any wind happening when you're confirming your 100 yard zero and at the 600 yard target.

You may want to print out the "Firing Solutions Check list" and check it before you go.

http://appliedballisticsllc.com/ballistics-educational-resources/articles/

 

[sled_mack]

Feedback after the range trip-
I started by confirming my zero at 100 yards and checking MV at the same time. What I found there surprised me - my MV was up 50 fps from what it was last fall. Same lot of powder, same lot of bullets. Brass is Lake City all from the same year. Temp last fall (early Sep) was 80 deg F. Temp on Monday when I was doing this was 86 deg F. Round count last year was at 1100, now is 1950. The MV change is a separate issue.

But, putting in this new MV had me hitting targets out to 800 yards. (Paper at 300, steel at 500, 600, 800, and 1030.) The different drag models (CDM, G1, G7) were all within a tenth at those distances. So functionally, no different and all accurate. I took some shots at the 1030 steel. There was a guy next to me trying to spot. We could see my misses, but neither could confirm that the lack of a dirt splash was a hit on steel. Just not enough energy left on steel that is hard mounted on posts.

Overall, a learning process for me. Both what I read on here and realizing that I need to keep better tabs on my equipment changing over time. Thanks to everyone for their input.

I repeated the same test with my AR-10 shooting 168 SMK. Round count much lower on this barrel, and no change in MV. So the solutions were all spot on out to 800 yards. What was interesting - I took some shots at the 1030 target. I could hear the ring from the heavier bullet. But my misses were way, way off the plate. Like 20 feet. Probably 2/3 of the shots were impacts or very close, and 1/3 were random far misses. I know this bullet is not known for handling subsonic transition very well, but I was surprised at how random the impacts were. And this was early enough in the morning that there wasn't a wind flag moving anywhere. I only use this rifle out to 700 yards, so I just was doing this to see what happens - learned something there for sure.

Last up was a 308 bolt gun shooting 178 Amax. I just put on new rail and scope mount to match up to a PVS30 clip on, so the scope height was much higher now. Zeroed over the chrono, no change in MV from last year. Entered the data and solid hits out to 1030. Misses out there were all wind related. Between eating lunch and zeroing scope caps the wind had a chance to kick up.

In the end, I'm glad I had more than one rifle with me. Had I seen the MV change on the first one all by itself, I would have been questioning the chrono. But having two other rifles chrono at the same MV as last year, gave me confidence in the chrono numbers. And the Kestrel/AB numbers giving me solid hits really sealed my confidence.

 

[Kobyashi72]

Glad to read you had success.

The MV variation can be managed using the MV-Temp tables in the Kestrel.

The AR-10 at 1030 could also be where your ammo is starting to fall outside of the extreme spread.

I started logging what the predictions for a 10-shot series equals in order to see where the ammo starts to fall outside the target

 

[sled_mack]

Kobyashi - I realize that I need to get enough values to populate the MV tables. But, 50 fps over 6 deg F using Varget seems like a lot? I log everything when I get to the range and get MV data. I just don't get to do it often enough. I've now got some warm weather MV, I'll have to make it a point to get more data this fall as the temps cool down.

I'm trying to understand the table. The Predicted POI is the elevation needed to hit the target, correct? In MILs? So you assume center hold on the target, know the target size, and if the elevation call is off my more than half of the target size you can predict a miss. Am I on the right track?

That is very cool. What are you using to drive the spreadsheet?

But my AR-10 was off by 5 MILs or more on some shots. I think that is more than just the ES catching up to me? Some were good elevation, just off to the side at the edge of my field of view in the scope. I took those shots just to see if I could hit the target. It is much further than I intend to regularly shoot that rifle with that ammo. As long as I can hit reliably at 800 yards, I'm happy.

Thanks.

 

[Kobyashi72]

Kobyashi - I realize that I need to get enough values to populate the MV tables. But, 50 fps over 6 deg F using Varget seems like a lot? I log everything when I get to the range and get MV data. I just don't get to do it often enough. I've now got some warm weather MV, I'll have to make it a point to get more data this fall as the temps cool down.

I'm trying to understand the table. The Predicted POI is the elevation needed to hit the target, correct? In MILs? So you assume center hold on the target, know the target size, and if the elevation call is off my more than half of the target size you can predict a miss. Am I on the right track?

That is very cool. What are you using to drive the spreadsheet?

But my AR-10 was off by 5 MILs or more on some shots. I think that is more than just the ES catching up to me? Some were good elevation, just off to the side at the edge of my field of view in the scope. I took those shots just to see if I could hit the target. It is much further than I intend to regularly shoot that rifle with that ammo. As long as I can hit reliably at 800 yards, I'm happy.

Thanks.

I agree The AR-10 is most likely off because the 168 SMK has a reputation for not doing well in trans.

The table going from left to right is the recorded MV for the shot in the series. And the BC would be for that shot to = the “predicted POI” in mils

The Last row is the totaled average of each column.

Which are the “averages” the Kestrel is going to “output” to you when you input those numbers

It was originally an exercise I went through to see the differences between adjusting a BC average vs MV averages. (Which now I would choose MV over BC in most cases)

 

[DocUSMCRetired]

I agree The AR-10 is most likely off because the 168 SMK has a reputation for not doing well in trans.

The table going from left to right is the recorded MV for the shot in the series. And the BC would be for that shot to = the “predicted POI” in mils

The Last row is the totaled average of each column.

Which are the “averages” the Kestrel is going to “output” to you when you input those numbers

It was originally an exercise I went through to see the differences between adjusting a BC average vs MV averages. (Which now I would choose MV over BC in most cases)

You need to spin that 168 SMK. It does much better then. Essentially, there is no reason not to have a 1 in 8 or 1 in 10 when using 0.308. I personally would not generally consider any barrel in the centerfire world that was at 10 or slower realistically. I use a 1 in 7 or 8 in nearly everything from 0.243 to 0.375 and up.

If you have a good barrel, and you have a good bullet, give it a fast twist.

 

[Kobyashi72]

You need to spin that 168 SMK. It does much better then. Essentially, there is no reason not to have a 1 in 8 or 1 in 10 when using 0.308. I personally would not generally consider any barrel in the centerfire world that was at 10 or slower realistically. I use a 1 in 7 or 8 in nearly everything from 0.243 to 0.375 and up.

If you have a good barrel, and you have a good bullet, give it a fast twist.

Any preferences or trade offs between 7 vs 8?

 

[DocUSMCRetired]

Any preferences or trade offs between 7 vs 8?

For me, no. I live at around 400 ft altitude. So I run fast barrels. In the winter time with a 140 Hybrid in my 6.5x47L I can actually reach an SG below 1.5 with a 1 in 8 twist barrel. Which means I am leaving optimized performance on the table. With a number of manufacturers making good bullets that have no issues in fast twist barrels, there is no reason to run them slow.