Precision Rifle Gear Kestrel bullet library question?

[smokinbobf4]

sorry if this is a dumb question, but I can’t seem to find the answer. I just went to add a new profile into my 5700 elite ab kestrel and am using the Berger 109 lrht . There are about 50 different bullet profiles and they all have that bullet and (xxxxxx) after them. What is the meaning of all of them? Also, if you use the custom curve, does it even matter?

 

[Nik H]

Just my 2 cents but others may be more knowledgeable

1. I believe that the ones called (XXXX) are different loadings and submitted to AB from trusted sources. I can't remember where I read it but that is what I remember.
2. I stick with G1/G7 curves because I can true the curve to fit actual DOPE. I don't think you can do that with the custom curve.

Hopefully, these are correct answers

 

[Maurygold]

No those are profiles for people shot over their radar. The one closest to your real speed is the one you should use because bc changes with mv. The closest one to your speed will be closest to your real bc.

 

[Nik H]

No those are profiles for people shot over their radar. The one closest to your real speed is the one you should use because bc changes with mv. The closest one to your speed will be closest to your real bc.

That is it...thanks for letting us know

 

[smokinbobf4]

I was wondering if that was the case but a lot of the number are only 3 long and the ones that have 4 are low. Like not velocity numbers. 1xxx etc. I agree with not using the custom curve so you can adjust. More curiosity.

 

[6.5SH]

I was wondering if that was the case but a lot of the number are only 3 long and the ones that have 4 are low. Like not velocity numbers. 1xxx etc. I agree with not using the custom curve so you can adjust. More curiosity.

{PDM} = Personal Drag Model the other number is so the person who shot it can find it in the list. They will have a print out from the mobile lab with that number and the session data.

If you select one you can choose between the AB custom curve, G1 and G7 as all of that was measured. As stated above these are of limited value as it wasn't your rifle and you have no idea what the velocity was. The curves are going to be different if it was a mild gas gun load Vs a 6mm AI +P Super Duty Barrel Burner Mach 20.

 

[smokinbobf4]

Got it! Thanks! Kind of strange they have all of them on there. Couldn’t even find just the standard one for a starting point. Maybe I need to look better.

 

[kthomas]

A small sidetrack:

Does the library have CDM's for the 220 LRHT's?

I couldn't find them a couple of weeks ago when I looked.

 

[6.5SH]

Got it! Thanks! Kind of strange they have all of them on there. Couldn’t even find just the standard one for a starting point. Maybe I need to look better.

The Berger 109 LRHT is in my list with a CDM available. Make sure your app and the database are up to date. IIRC you also periodically need to let the app connect to your Kestrel Elite to keep certain features unlocked.

 

[6.5SH]

A small sidetrack:

Does the library have CDM's for the 220 LRHT's?

I couldn't find them a couple of weeks ago when I looked.

It shows in the list in my app.

 

[kthomas]

It shows in the list in my app.

Wonder why I couldn't find them? I just updated it too. I'll look again.

 

[6.5SH]

Wonder why I couldn't find them? I just updated it too. I'll look again.

Mine is on Android, Build 300, Ballistic Database 319800

 

[vh20]

Just my 2 cents but others may be more knowledgeable

1. .
2. I stick with G1/G7 curves because I can true the curve to fit actual DOPE. I don't think you can do that with the custom curve.

Yes, you can. Select the factory CDM for your bullet. Establish a GOOD zero and MV Average for your rifle and load, and then run the MVCal procedure in the Kestrel. It will give you a distance where your bullet “should” be at 1.2 Mach (beginning of Transonic). Set up a target within 10% of this distance, but not OVER. I generally try to get one set somewhere around 90-95% of the distance given, and it has to be measured EXACTLY. Then you dial the elevation the Kestrel computes for that target, fire a group and establish the center of that group. Compare the vertical impact to the aimpoint and if it is off, measure how far it’s off in mils using your reticle. If the given solution was 14.0 mils and your group was 0.2 low, go into the MVCal menu and adjust the solution from 14.0 (calculated) to 14.2 (actual). The Kestrel will then re-adjust your solution to that curve for all target distances and it works very well.
There is a similar procedure called Drop Scale Factor for targets farther out as the bullet enters the subsonic region and the curve changes again. It is done in a very similar way, just at farther distances. So you end up with two curves being established - one for supersonic and one for subsonic. The Kestrel knows which one to use for your solution based on the target distance you input.

 

[Nik H]

Yes, you can. Select the factory CDM for your bullet. Establish a GOOD zero and MV Average for your rifle and load, and then run the MVCal procedure in the Kestrel. It will give you a distance where your bullet “should” be at 1.2 Mach (beginning of Transonic). Set up a target within 10% of this distance, but not OVER. I generally try to get one set somewhere around 90-95% of the distance given, and it has to be measured EXACTLY. Then you dial the elevation the Kestrel computes for that target, fire a group and establish the center of that group. Compare the vertical impact to the aimpoint and if it is off, measure how far it’s off in mils using your reticle. If the given solution was 14.0 mils and your group was 0.2 low, go into the MVCal menu and adjust the solution from 14.0 (calculated) to 14.2 (actual). The Kestrel will then re-adjust your solution to that curve for all target distances and it works very well.
There is a similar procedure called Drop Scale Factor for targets farther out as the bullet enters the subsonic region and the curve changes again. It is done in a very similar way, just at farther distances. So you end up with two curves being established - one for supersonic and one for subsonic. The Kestrel knows which one to use for your solution based on the target distance you input.

Thanks for that. I wasn't aware that this process worked for CDM.

How do you accurately measure a distance that long?

 

[vh20]

Thanks for that. I wasn't aware that this process worked for CDM.

How do you accurately measure a distance that long?

I use a Terrapin X. But the distances aren't really "that" long. Even for my 300NM, you're still only looking at something around 1300 yds for MVCal and a lot of less expensive LRFs will work at that distance. Where I run into difficulty is doing the Drop Scale Factor (DSF) because it allows you to establish points along the curve out to the farthest distance you want to shoot. It takes a good LRF and access to really long distances that I don't often get to shoot (my range goes to 1625 but the DSF curve in the Kestrel starts beyond that (maybe 1800?) for the 300NM.
Here's some videos with Todd Hodnett explaining why/how to do it (Kestrel has their own videos as well, but they only go into "how" whereas Hodnett explains "why" you should).

A quick one from Kestrel on "how":



More in-depth from Hodnett:

 

[Nik H]

I use a Terrapin X. But the distances aren't really "that" long. Even for my 300NM, you're still only looking at something around 1300 yds for MVCal and a lot of less expensive LRFs will work at that distance. Where I run into difficulty is doing the Drop Scale Factor (DSF) because it allows you to establish points along the curve out to the farthest distance you want to shoot. It takes a good LRF and access to really long distances that I don't often get to shoot (my range goes to 1625 but the DSF curve in the Kestrel starts beyond that (maybe 1800?) for the 300NM.
Here's some videos with Todd Hodnett explaining why/how to do it (Kestrel has their own videos as well, but they only go into "how" whereas Hodnett explains "why" you should).

A quick one from Kestrel on "how":



More in-depth from Hodnett:

OK...sounds good. I use a RAPTAR so that will work

 

[vh20]

Sure enough!
I had a professional surveyor come to my range and we established accurate-to-within-0.5 inch-distances at four permanently marked points from 740 to 1626 yards. We use this not only for shooting known-distance targets, but also to test/calibrate any LRF you happen to have. The Terrapin X is within a yard at 1626. We've tested quite a few LRFs and the results are sometimes disappointing.

 

[Nik H]

We've tested quite a few LRFs and the results are sometimes disappointing.

I could believe that.

 

[smokinbobf4]

Very good info! Thanks!

 

[smokinbobf4]

I found the regular one after a little closer look. Thanks again for the help!