How True is True??

Mt_Hunt · Sep 15, 2018

Kind of an odd way to word a question but I have been trying to figure out Truing with BC and MV on my Kestrel Elite w/AB for awhile. I have listened to every podcast that Frank talks about it in anyway.. I have the AB app on my phone also and pry 3 other various calculators...

My dope has always been close but the T of WTF has always nagged in my mind, is it really on? I went out today, first time shooting in awhile, lots of dry snaps and I rezeroed.

I have a 6XC running hand loaded 110smks @ 2985fps, BC was set for G1 of .617 which is Sierras number off the box. Anyway I didn't bother with a MV check went with my old MV number. Zero is spot on at 100 and rifle is shooting nice, did 3 rounds at each of the distances on my range. Wind was from 5 o'clock at 5-8mph, not much wind hold compared to normal.
My yardages are 305, 545, 586, 686, 1015, and 1223, I have a clump of trees that block me from having 800 and 900 targets..

I wrote all my atmospherics down and went off my Kestrel for try dope cause I know it is close. Shot 3 at every target, if I was low are high on my targets water line I reshot and wrote down try dope and actual dope. Out to 1015 it was actually right on, this surprised me cause I usually have trouble at the 1000 it has funky mirage and is in a shadowed area that is hard to to see misses. At 1223 I was off, try dope was 32.5moa actual needed was 33.5. only 1 moa off so I figured I could just lower the BC some. I tried small adjustments and big adjustments and could get the 1223 to line up but it was throwing my other numbers off buy a 1/4 to 1/2 minute.. I messed with it more and got it so I was on or within a 1/4 minute of actual...

Thats where my question comes in, how true is true? If your within a 1/4 minute or a tenth mil is it close enough? Considering this I assume shooter error be more than this?

Side note I took my atmospheric numbers and plugged everything into a New track into the AB app on my phone so it was the same as the Kestrel.. To try something I just plugged the longest yardages and actual drop into the Calibration mode on the app and all it did was lower my MV 10fps to 2975, and it lined up to my actual numbers. Again how true is true? Maybe I am overthinking or to OCD, but it got me thinking, so I figured I would ask smarter shooters than me.

MarinePMI · Sep 15, 2018

DSF (I think) is how AB trues the BC. Their "truing function" actually just adjusts the velocity. Also, when truing, as I understand it, you need to have all the extra stuff turned off (spin drift, aerodynamic jump (wind set to zero), corialis calculation, etc.).

I'm sure Doc could jump in here and add some content...

Deleted member 113831 · Sep 15, 2018

I have no idea what your conditions and terrain were, but you have to shoot it in a light neutral (overcast or at least very early morning) condition to really determine whether it is a ballistic problem or an optical one. Lots of things can be screwy at the ranges you are talking about.

Dope just doesn't go all to hell in 200 yards. I suspect there is another cause.

FingerBlaster · Sep 15, 2018

One issue with bc numbers is that they vary based on velocity. Ie you bc at the muzzle will be different than say 500y down range, which is different yet than 1,000 down range. The custom drag curves help with that.

Mt_Hunt · Sep 15, 2018

MarinePMI said:
DSF (I think) is how AB trues the BC. Their "truing function" actually just adjusts the velocity. Also, when truing, as I understand it, you need to have all the extra stuff turned off (spin drift, aerodynamic jump (wind set to zero), corialis calculation, etc.).

I'm sure Doc could jump in here and add some content...

I did turn all that stuff off. Was using wind zone 2 for approximate wind hold but and see if it was giving me right info. I don’t have the crazy distance they want for the DSF was tying to see if the Frank way was going to work cause it makes more sense to me.

uncoffeed · Sep 15, 2018

I don't know. I understand the theory behind truing at huge distances (near transonic), but I'm not at all convinced of the practicality of that approach. The variables involved in making a 1223 yard shot with a 6xc are pretty difficult to keep in check. I usually true to about 900 or 1000, which is pretty much the limit of my confidence in calling misses and the reasons therefore.
I have no doubt that AB would be pretty accurate in predicting an impact at 1223 yards if the operator was able to precisely detail all variables. In reality, little updrafts and downdrafts and crosswinds and mirage pockets and the lighting conditions that are so in vogue now are all effectively incalculable.

I admit I don't have regular access to a 1200+ yard range, but when I do shoot it at matches and events, my dope is usually pretty much on. If I'm getting misses at these ranges I generally don't blame my solver first. I assume the wind/ranging error/butterfly flapping its wings is the issue.

In reality, I rarely have to true more than about +/- .005 in G7 BC from what I get from Litz or from this forum. I use my Magnetospeed to get a good 15+ round average velocity. Then I plug in the BC from Litz or the manufacturer or from someone here using a similar twist barrel as my own. Then I do the process outlined below.

When I'm truing to 800 or 900 yards, I'm not "waterlining the target" and measuring offset through my scope. Well, I am, but I also go down range and measure offset from POA with a measuring tape. Then I convert back that measurement to mils. So if I'm truing at 950 yards, I dial the 6.7mil my solver says I should dial. Then I fire my 3+shot group. I get a rough idea of the correction through my scope (.1mil increments). I note everything in my book. At some point (usually after I'm done shooting), I'll head down range and measure the actual offset in inches between my aim point and the center of the group on target- say 1.8" low. That's .05mil. So I'll fiddle with my solver to account for that.
As a note, I also true with my chronograph attached, and note the velocity of every round fired along with its impact position on target. It doesn't really seem to equate to anything, but it's data.
I do like to true multiple times in different conditions. It gives me an average. I average pretty much everything. If I'm truing, I assume that there are ranging variables and the like, so I average the truing result over 700, 800, 900 yards. Then I average the truing results I accumulate over multiple sessions. Usually doesn't make a huge difference in results, but it adds a lot of confidence and it helps me resolve some odd conclusions based on anomalous results.
I also keep track of data from matches and events. For long range stages, I always take fresh record my environment data and I take special mental note of my impacts. Then I write the info down after the stage/shoot. It's all data.

Ballistic truing is a simple process, but obtaining accurate results takes time and attention. If you're trying to true in one session with fewer than 20 rounds, you're not going to get great results. Truing is a part of learning your gun. It's a process.

YMMV.

Mt_Hunt · Sep 15, 2018

uncoffeed said:
I don't know. I understand the theory behind truing at huge distances (near transonic), but I'm not at all convinced of the practicality of that approach. The variables involved in making a 1223 yard shot with a 6xc are pretty difficult to keep in check. I usually true to about 900 or 1000, which is pretty much the limit of my confidence in calling misses and the reasons therefore.
I have no doubt that AB would be pretty accurate in predicting an impact at 1223 yards if the operator was able to precisely detail all variables. In reality, little updrafts and downdrafts and crosswinds and mirage pockets and the lighting conditions that are so in vogue now are all effectively incalculable.

I admit I don't have regular access to a 1200+ yard range, but when I do shoot it at matches and events, my dope is usually pretty much on. If I'm getting misses at these ranges I generally don't blame my solver first. I assume the wind/ranging error/butterfly flapping its wings is the issue.

In reality, I rarely have to true more than about +/- .005 in G7 BC from what I get from Litz or from this forum. I use my Magnetospeed to get a good 15+ round average velocity. Then I plug in the BC from Litz or the manufacturer or from someone here using a similar twist barrel as my own. Then I do the process outlined below.

When I'm truing to 800 or 900 yards, I'm not "waterlining the target" and measuring offset through my scope. Well, I am, but I also go down range and measure offset from POA with a measuring tape. Then I convert back that measurement to mils. So if I'm truing at 950 yards, I dial the 6.7mil my solver says I should dial. Then I fire my 3+shot group. I get a rough idea of the correction through my scope (.1mil increments). I note everything in my book. At some point (usually after I'm done shooting), I'll head down range and measure the actual offset in inches between my aim point and the center of the group on target- say 1.8" low. That's .05mil. So I'll fiddle with my solver to account for that.
As a note, I also true with my chronograph attached, and note the velocity of every round fired along with its impact position on target. It doesn't really seem to equate to anything, but it's data.
I do like to true multiple times in different conditions. It gives me an average. I average pretty much everything. If I'm truing, I assume that there are ranging variables and the like, so I average the truing result over 700, 800, 900 yards. Then I average the truing results I accumulate over multiple sessions. Usually doesn't make a huge difference in results, but it adds a lot of confidence and it helps me resolve some odd conclusions based on anomalous results.
I also keep track of data from matches and events. For long range stages, I always take fresh record my environment data and I take special mental note of my impacts. Then I write the info down after the stage/shoot. It's all data.

Ballistic truing is a simple process, but obtaining accurate results takes time and attention. If you're trying to true in one session with fewer than 20 rounds, you're not going to get great results. Truing is a part of learning your gun. It's a process.

YMMV.

Good info thanks... I first did try litz bc and his custom curve for the 110smks and it was actually off more than the sierra G1 BC..
I have tried lots of things to true up different apps and they are all close but hard to get just right..

Very good explanation on your method and will for sure double check it again. Have a shorter range match coming up with small targets that's why I was wondering.. I mean it's a decision if you round up or down when you get a dope on the kestrel of 13.87 moa so do you go down to the .75 or up to 14 even.. That's the fine line of how true can you get it.. I am for sure happy with everything being money inside 1100.. 1200+ is dicey with a 6mm for sure and shooter error might be a bigger factor.

I have to true my 28 Nosler soon and will try to track what it does similarly..

I use a magneto but I cant true with mine attached it usually shifts poi to much.

Kobyashi72 · Sep 15, 2018

Mt_Hunt said:
Good info thanks... I first did try litz bc and his custom curve for the 110smks and it was actually off more than the sierra G1 BC..
I have tried lots of things to true up different apps and they are all close but hard to get just right..

Very good explanation on your method and will for sure double check it again. Have a shorter range match coming up with small targets that's why I was wondering.. I mean it's a decision if you round up or down when you get a dope on the kestrel of 13.87 moa so do you go down to the .75 or up to 14 even.. That's the fine line of how true can you get it.. I am for sure happy with everything being money inside 1100.. 1200+ is dicey with a 6mm for sure and shooter error might be a bigger factor.

I have to true my 28 Nosler soon and will try to track what it does similarly..

I use a magneto but I cant true with mine attached it usually shifts poi to much.

Here some things to consider.

Re-check the Custom Curve and Litz BC with the direction-of-fire and Latitude set for your location

Write down what your Latitude and the Azimuth the target is facing for your “records”

On a Kestrel

Go into “environment” and enter your location’s Latitude (it’s set to 40* by default where the kestrel factory is located)

Calibrate the compass on the Kestrel. Point the back of the kestrel toward the target

With “Tgt” highlighted press the capture button (red dash) in-between the “gear” and the “light” on a 5700 series

or the “Camera” button on a 4500 series.

Press the “capture” button again to lock that “heading” into the kestrel

or use the compass app on your phone and enter it manually in the kestrel

update the Azimuth and latitude inputs at the same time you update the environmental info when you travel to a new location/range

If you have data for MV-TEMP tables enter that to manage MV variation due to temperature

SD/Direction-of-Fire/Latitude/AJ should be on BEFORE you “True” the software.

MarinePMI · Sep 16, 2018

Kobyashi72 said:
If you have data for MV-TEMP tables enter that to manage MV variation due to temperature

SD/Direction-of-Fire/Latitude/AJ should be on BEFORE you “True” the software.

Pretty sure in one of Frank's Kestrel Podcasts they state the opposite of this...

Deleted member 113831 · Sep 16, 2018

What kind of ballistic error would allow the OP to be dead on from 300 to 1000 yards, and be off a full MOA at 1200 yards?

How accurste can "truing" be with omly 3 rounds per target?

Kestrel Ballistics · Sep 16, 2018

I second Skookum, good solutions out to 1000y and then a 12" error over the next 223y would cause me to try it again and confirm that is really happening. You should still be in supersonic range and not that much should be happening to the bullet at that distance.

Kobyashi72 · Sep 16, 2018

Skookum said:
What kind of ballistic error would allow the OP to be dead on from 300 to 1000 yards, and be off a full MOA at 1200 yards?

How accurste can "truing" be with omly 3 rounds per target?

Your guess is as good as mine

The OP stated:

“I just plugged the longest yardages and actual drop into the Calibration mode on the app and all it did was lower my MV 10fps to 2975, and it lined up to my actual numbers”.

(OP didn’t specify which of the “longest yardages” were used or if 1223 yd was included in his calibration exercise)

Skookum said:
How accurate can "truing" be with only 3 rounds per target?

As accurate as recorded D.O.P.E is with only 3 rounds per target.

Greg Langelius * · Sep 16, 2018

If all your CCB shot is off by at 1200yd is 1MOA, you're probably still near the head of the pack.

Most 'missed' wind calls are off by several times that at distances from 500yd and on out.

Let's take that apart. One MOA is 1/60th of one degree. The thirty MOA or so ballpark 1000yd come-up is still only 1/2 of one degree's difference between a dead on hit at 010yd and one at 1000yd. That's actually astounding to the non-perfectionist Average Joe

Greg

Kobyashi72 · Sep 16, 2018

MarinePMI said:
Pretty sure in one of Frank's Kestrel Podcasts they state the opposite of this...

The "C" in the C.R.U.S.H is Capture direction of fire (target azimuth)

Deleted member 113831 · Sep 16, 2018

Kobyashi72 said:
Your guess is as good as mine

The OP stated:

“I just plugged the longest yardages and actual drop into the Calibration mode on the app and all it did was lower my MV 10fps to 2975, and it lined up to my actual numbers”.

(OP didn’t specify which of the “longest yardages” were used or if 1223 yd was included in his calibration exercise)

As accurate as recorded D.O.P.E is with only 3 rounds per target.

You are a true wealth of knowledge and wisdom.

poeman446 · Sep 16, 2018

Check to make sure that your zero range is pretty close to 100 yards. I’ve done some boneheaded stuff before like zeroing at 60 yards and I could hit within a tenth out to about 400. Then it would slowly fall apart. At 1000 I was a full mil or more off. I’ve also had issues with Bore heighbcausong similar issues, but your data still sounds like it’s a much larger change over a much shorter distance. I can’t imagine what is causing you to be 12” off over 250 yards when your data was previously tracking correctly. Is your bullet transonic and going subsonic in this Range? It shouldn’t be at 1200 with a 110, but I guess it’s possible.

BLKWLFK9 · Sep 16, 2018

Sheesh.. if all your dope was spot on until 1223 yards and youre just 1 moa low, call it good bro.

Mt_Hunt · Sep 16, 2018

I

poeman446 said:
Check to make sure that your zero range is pretty close to 100 yards. I’ve done some boneheaded stuff before like zeroing at 60 yards and I could hit within a tenth out to about 400. Then it would slowly fall apart. At 1000 I was a full mil or more off. I’ve also had issues with Bore heighbcausong similar issues, but your data still sounds like it’s a much larger change over a much shorter distance. I can’t imagine what is causing you to be 12” off over 250 yards when your data was previously tracking correctly. Is your bullet transonic and going subsonic in this Range? It shouldn’t be at 1200 with a 110, but I guess it’s possible.

Haha yeah I have done that before too.. that looks like a 100 at it was 85 and everything was all outta whack.

I don’t know either but I will pry re shoot some and see what I come up with. I thought maybe the range was off but ranged it 5 or 6 times and all were the same or only a yard variation. It is a lot more on than it has been in the past. Only had my Kestrel since January and have always been close enough but I need to true all my stuff up for confidence and mental sanity.

Mt_Hunt · Sep 16, 2018

Kestrel Ballistics said:
I second Skookum, good solutions out to 1000y and then a 12" error over the next 223y would cause me to try it again and confirm that is really happening. You should still be in supersonic range and not that much should be happening to the bullet at that distance.

I will reshoot and see what my results are.. It seems odd to me as well to just be off.. Was easy to spot misses wind call was off but they all went low off the bottom corner of the plate. Dialed up 1 Moa and held 3 for wind and next 3 shots center hits.

Mt_Hunt · Sep 16, 2018

Kobyashi72 said:
Your guess is as good as mine

The OP stated:

“I just plugged the longest yardages and actual drop into the Calibration mode on the app and all it did was lower my MV 10fps to 2975, and it lined up to my actual numbers”.

(OP didn’t specify which of the “longest yardages” were used or if 1223 yd was included in his calibration exercise)

As accurate as recorded D.O.P.E is with only 3 rounds per target.

In my AB app I used 686yds 1015 and 1223yds I have not tried Anything in my Kestrel other than seeing if BC tweaks made a difference..

I will re shoot and double check my data and what I am getting for results..
How many rounds do I need to shoot at each target to be sure I have the right dope? If I hit it 3 for 3 at 1000 do I need the next 2? Do I need 5 at 500 yards to know for sure I hit ?
I am honestly asking cause it seems overly redundant to me..

Deleted member 113831 · Sep 16, 2018

Mt_Hunt said:
In my AB app I used 686yds 1015 and 1223yds I have not tried Anything in my Kestrel other than seeing if BC tweaks made a difference..

I will re shoot and double check my data and what I am getting for results..
How many rounds do I need to shoot at each target to be sure I have the right dope? If I hit it 3 for 3 at 1000 do I need the next 2? Do I need 5 at 500 yards to know for sure I hit ?
I am honestly asking cause it seems overly redundant to me..

If you are concerned about wasting rounds, you could eliminate about 3 of those yard lines. Shoot enough good rounds at 100 to get a good certain center of group, record any undialable offset, then shoot the 586, 1015, 1223 with at least 5 rounds a piece to get an decent group center. It will also give you a better idea of actual vertical dispersion.

Mt_Hunt · Sep 16, 2018

Skookum said:
If you are concerned about wasting rounds, you could eliminate about 3 of those yard lines. Shoot enough good rounds at 100 to get a good certain center of group, record any undialable offset, then shoot the 586, 1015, 1223 with at least 5 rounds a piece to get an decent group center. It will also give you a better idea of actual vertical dispersion.

Thanks will pry do that to double check.. Has all been good info. Not really concerned with conserving rounds.. Trying to somewhat keep with the no more than 3-5 per target and move on. Most matches here are shoot 2 or 3 per target, just a habit I have gotten into.

My main thing is how true can we really get since most times we have to round up or down to the nearest click anyway.

I will be switching to mils before the new year since I have a 50% off certificate for a new scope and will pry do it all over again with it.. Getting a good routine for doing so is my main focus. I have other rifles I plan on doing it with as well.

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