2400 ABS Calibration Question

[Kiddross]

Trying my darndest to figure this thing out.

Shooting today at 533 yards I was roughly 3/4 moa high from what it was telling me to shoot .

In hoping to calibrate it to this info I went into the calibration screen and it gave me 2 yardage groups to input into.

1st being roughly 820-900 yards and 2nd being 1200-1300 yards.

It allowed me to enter my yardage at 533 yards and my MOA which was 8.7.

What I noticed though is it would not save this info. It would say the speed was 3060 which it was already entered at but it would also say velocity set. However, when I'd go to look back at the calibration screen all parameters were empty.

I guess my question is, can I input my own yardage as I did or do you have to shoot between the parameters it gives you to work correctly ?

If so that seems extremely odd to me. Not to mention where I can shoot, it will be extremely difficult to find a place to shoot within it's exact given yardages.

Thanks for any input!


Sent from my ONEPLUS A6013 using Tapatalk

 

[hereinaz]

Find transonic for your cartridge. True velocity up to that distance. Increase or decrease velocity so it matches. Also, make sure you have all the other inputs correct before you calibrate.

Also, keep the rangefinder out of the sun, it will affect the on board temperature sensor.

The calibration in the rangefinder is for transonic and beyond, that's why it gives you such long distances.

 

[hereinaz]

Google this:

applied ballistics how to true velocity

First result for me is a PDF by Applied Ballistics on truing. Sorry, can't get the link to the PDF from my phone.

 

[wind gypsy]

How confident are you that your input data is correct? At that range, velocity is typically the biggest factor. The truing function is for much longer ranges.

 

[BRTreedogs]

So this is what I have done ad im not sure its correct but seems to work so far.

I usually shoot at around 500 and true the ballistics using the velocity.
Then a stretch out to as far as you can make consistent hits. For me 750 the I tweak the BC a little. And the velocity some more.

I haven't been able to get a hit at 1200 yet.
And I haven't found a way to get the perfect ballistic arc to match my round perfectly.

I figured true it up as far as possible because the margin for error is larger the closer in.

For instance I'm about 3" high at 500 w my ballistics tried up at 750.

@Broz @Ryan Avery

You both have alot of experience with the kilo.

 

[wind gypsy]

So this is what I have done ad im not sure its correct but seems to work so far.

I usually shoot at around 500 and true the ballistics using the velocity.
Then a stretch out to as far as you can make consistent hits. For me 750 the I tweak the BC a little. And the velocity some more.

I haven't been able to get a hit at 1200 yet.
And I haven't found a way to get the perfect ballistic arc to match my round perfectly.

I figured true it up as far as possible because the margin for error is larger the closer in.

For instance I'm about 3" high at 500 w my ballistics tried up at 750.

@Broz @Ryan Avery

You both have alot of experience with the kilo.

What are you using for BC input?

I've found that if you're using an ABM custom ballistic curve for your bullet it works well to adjust velocity to 6 or 700 yards and tweak BC if you're off beyond that. All the bullets I've used with my kilo to any significant distance have had a custom BC curve so I can't say how it works with just a g1 or g7 value.

The other thing to keep in mind is once you start stretching things out up or down drafts can mess with your data quite a bit.

 

[hereinaz]

So this is what I have done ad im not sure its correct but seems to work so far.

I usually shoot at around 500 and true the ballistics using the velocity.
Then a stretch out to as far as you can make consistent hits. For me 750 the I tweak the BC a little. And the velocity some more.

I haven't been able to get a hit at 1200 yet.
And I haven't found a way to get the perfect ballistic arc to match my round perfectly.

I figured true it up as far as possible because the margin for error is larger the closer in.

For instance I'm about 3" high at 500 w my ballistics tried up at 750.

@Broz @Ryan Avery

You both have alot of experience with the kilo.

If the rangefinder is in the sun or comes from a hot car, it will cause you to shoot high, because the temperature sensor is affected by the units temp. With a Kestrel, thst is why you swing it around and the temp sensor is out of the actual body.

 

[BRTreedogs]

What are you using for BC input?

I've found that if you're using an ABM custom ballistic curve for your bullet it works well to adjust velocity to 6 or 700 yards and tweak BC if you're off beyond that. All the bullets I've used with my kilo to any significant distance have had a custom BC curve so I can't say how it works with just a g1 or g7 value.

The other thing to keep in mind is once you start stretching things out up or down drafts can mess with your data quite a bit.

Well I quit using the ABS because it won't tell you what they are and you can't tweak it.

My main problem is no accurate chrono to i just guess then walk the rounds in to the plate.
Then true up velocity.

 

[BRTreedogs]

If the rangefinder is in the sun or comes from a hot car, it will cause you to shoot high, because the temperature sensor is affected by the units temp. With a Kestrel, thst is why you swing it around and the temp sensor is out of the actual body.

Yeah I'm talking back to back rounds with just enough time to go move the plate all the stuff sitting under a juniper.

I can't get the arc true perfectly with the kilo abs or the free hornady app.
Seems to me you can only get it perfect at a single range.
Unless you just go old school and shoot them record on cards.

 

[hereinaz]

What are you using for BC input?

I've found that if you're using an ABM custom ballistic curve for your bullet it works well to adjust velocity to 6 or 700 yards and tweak BC if you're off beyond that. All the bullets I've used with my kilo to any significant distance have had a custom BC curve so I can't say how it works with just a g1 or g7 value.

The other thing to keep in mind is once you start stretching things out up or down drafts can mess with your data quite a bit.

Besides drafts, aerodynamic jump and shooting position all have an effect that will prevent good truing.

It is a hard truth to learn that the shooter is often unaware of their own shooting faults that contaminate the truing process. I know my first couple years were steep learning curves. I had to cut out garbage I had done to "true" dope as I improved. Just be aware it might be something else.

 

[hereinaz]

Yeah I'm talking back to back rounds with just enough time to go move the plate all the stuff sitting under a juniper.

I can't get the arc true perfectly with the kilo abs or the free hornady app.
Seems to me you can only get it perfect at a single range.
Unless you just go old school and shoot them record on cards.

Google "weaponized math" and download the spreadsheet. Helps you easily gather your dope on hard copy. Best old school method I have seen.

I personally don't like the 2400 ABS because it is quirky and doesn't fit the way I shoot and hunt.

 

[BRTreedogs]

Google "weaponized math" and download the spreadsheet. Helps you easily gather your dope on hard copy. Best old school method I have seen.

I personally don't like the 2400 ABS because it is quirky and doesn't fit the way I shoot and hunt.

Unfortunately with no mentors learning to shoot long range by reading forums and YouTube is a long road to hoe.
It took me hours and hours of shifting thru threads with years of different ways of doing it for me to have any idea on how to even get something going at 500

 

[hereinaz]

Unfortunately with no mentors learning to shoot long range by reading forums and YouTube is a long road to hoe.
It took me hours and hours of shifting thru threads with years of different ways of doing it for me to have any idea on how to even get something going at 500

I have been there... I don't have anyone local as a mentor. I shot a couple years of local matches and a couple two day matches of PRS, and that was a great help getting an idea and some coaching. Its not as much fun for me now, cause it was about learning. To improve more, I would have to practice specifically for that. I spend more time shooting specific to hunting now.

Fortunately, I was able to connect with a group of shooters, on Facebook, believe it or not... I am in an admin group for the Long Range Shooters, and among them are multiple snipers, sniper instructors, AMU shooters and coaches, industry professionals, and serious ELR enthusiasts. I trained with some in person and that was HUGE. In person training is absolutely worth it.

Just the other day in the admin group, they were going over truing and talking about what they learned, like recent stuff.

In the conversation about truing, everyone came back to this-- true muzzle velocity only during supersonic and then use the truing function in Applied Ballistics. One of them ran through the actual effect of truing BC and showed it wasn't effective.

On Rokslide, make sure to check out the subforum Long Range Tips. I am starting at the super simple fundamentals, but those are what really got me on track.

 

[Kiddross]

Awesome info and Dialog gents! It is really appreciated and some great info to think about.
The comment on updrafts is a good think to keep in mind. We were shooting over a unit on the warmest day of the year we have had. Wind was next to nill but I imagine the thermals were pushing up the hill a good amount.

One interesting aspect is the BC. Applied ballistics has the 150 ABLR at a much lower BC than what Nosler advertises. I understand that the Applied ballistic is a true average over speed and Nosler is more so the highest BC the bullet will see. However, When I overwrite the Applied ballistics BC and put in the .485 that Nosler states, This put my MOA in line with actuals that it took to make the shot. IT may have been coincident but I found it interesting.

My next step is going to be test it with using the Custom Curve Coefficients and see what it does.

For what I do...Shooting out to 800 or so. It sounds like I need to leave the calibration alone. Find the Coefficient factor that works best and fine tune the velocity from there.

I really wish you could extract the hard data from the 2400 ABS so you could compare changes made. With todays atmosphere, I do not have a limited amount of ammo to play with while nailing this down.

Thanks again for all the info!

 

[hereinaz]

I always get into the specific question asked, assuming other variables are not in play. If you can't true with using muzzle velocity, then check inputs. One input is scope tracking.

I think MORE common than ballistic software errors are scope tracking errors.

If your scope tracks off by 5%, at 500 software might be on with 5% error of adjustment for 6 mil for me. 5% is .3 mil, about 1 moa or about 5 inches. But then at 800 yards, you can have more than twice as many clicks. Though the error is only 5%, the amount if adjustment goes up to 13 mil so the error is now .65 mil or about 2.25ish moa. But, go to 1000, 20 mil and now the error is 1 mil or 3.5 moa.

The difference in dialing error in dope between 500 yards of about 5 inches and 800 yards of about 18 inches is significant. Your solver can't make a curve to match what you have to dial, unless it builds in the tracking error.

If you have a broken ruler, the scope turrets, then you will never be able to true the data.

So, OP and BRtreedogs, your scope could easily be the problem with the software "truing".

Everyone with issues truing should tall target test their scope first. It matters.

 

[hereinaz]

Awesome info and Dialog gents! It is really appreciated and some great info to think about.
The comment on updrafts is a good think to keep in mind. We were shooting over a unit on the warmest day of the year we have had. Wind was next to nill but I imagine the thermals were pushing up the hill a good amount.

One interesting aspect is the BC. Applied ballistics has the 150 ABLR at a much lower BC than what Nosler advertises. I understand that the Applied ballistic is a true average over speed and Nosler is more so the highest BC the bullet will see. However, When I overwrite the Applied ballistics BC and put in the .485 that Nosler states, This put my MOA in line with actuals that it took to make the shot. IT may have been coincident but I found it interesting.

My next step is going to be test it with using the Custom Curve Coefficients and see what it does.

For what I do...Shooting out to 800 or so. It sounds like I need to leave the calibration alone. Find the Coefficient factor that works best and fine tune the velocity from there.

I really wish you could extract the hard data from the 2400 ABS so you could compare changes made. With todays atmosphere, I do not have a limited amount of ammo to play with while nailing this down.

Thanks again for all the info!

Was the rangefinder in the sun? If it had warmer temps, that will screw with dope all along the curve.
What scope?
Have you tall target tested it?

You don't need a chronograph. Zero at 100 perfectly and then shoot at 300 without touching the turrets. You will hit low, so put a tall piece of paper out there. Measure how low it hit and then adjust velocity till it matches. Then tune from there.

 

[Kiddross]

Was the rangefinder in the sun? If it had warmer temps, that will screw with dope all along the curve.
What scope?
Have you tall target tested it?

You don't need a chronograph. Zero at 100 perfectly and then shoot at 300 without touching the turrets. You will hit low, so put a tall piece of paper out there. Measure how low it hit and then adjust velocity till it matches. Then tune from there.

RAZOR HD AMG is the Scope. That is a great Idea to pursue a tracking test. I guess my hope is a scope of this quality would be dead nuts (It comes back to zero) However, Nothing is perfect and I need to check this.

I was checking the rangefinder for temps. When I first pulled it out it was reading 92 degrees. I set in in the shade and in a few minutes it was down to 62 deg. Which was accurate for our weather.

That is a fantastic idea to measure the drop at 300 and adjust the velocity to match. Can you confirm for this exercise...

- Make sure rifle is dead on at 100
-Shoot a round at 300. Lets say 5 rounds.
-Average the 5 rounds and their associated drop. Let's say average is 9.7 inches.
-2400 ABS states 10.3" Drop.
-Adjust Speed in the Sig app until its ballistic solver matches the MOA needed for the 9.7" Drop?

It very well could be a chrono issue. I had come up with an average speed of 3053 utilizing a 5 shot average from a not very good chrono. ( PRO Chrono)

 

[Kiddross]

I always get into the specific question asked, assuming other variables are not in play. If you can't true with using muzzle velocity, then check inputs. One input is scope tracking.

I think MORE common than ballistic software errors are scope tracking errors.

If your scope tracks off by 5%, at 500 software might be on with 5% error of adjustment for 6 mil for me. 5% is .3 mil, about 1 moa or about 5 inches. But then at 800 yards, you can have more than twice as many clicks. Though the error is only 5%, the amount if adjustment goes up to 13 mil so the error is now .65 mil or about 2.25ish moa. But, go to 1000, 20 mil and now the error is 1 mil or 3.5 moa.

The difference in dialing error in dope between 500 yards of about 5 inches and 800 yards of about 18 inches is significant. Your solver can't make a curve to match what you have to dial, unless it builds in the tracking error.

If you have a broken ruler, the scope turrets, then you will never be able to true the data.

So, OP and BRtreedogs, your scope could easily be the problem with the software "truing".

Everyone with issues truing should tall target test their scope first. It matters.

Is there an input in the app to enter the tracking error if there is one?

 

[hereinaz]

Is there an input in the app to enter the tracking error if there is one?

This is the phone app. Should be one in the ABS when setting up the rifle.

 

[hereinaz]

RAZOR HD AMG is the Scope. That is a great Idea to pursue a tracking test. I guess my hope is a scope of this quality would be dead nuts (It comes back to zero) However, Nothing is perfect and I need to check this.

I was checking the rangefinder for temps. When I first pulled it out it was reading 92 degrees. I set in in the shade and in a few minutes it was down to 62 deg. Which was accurate for our weather.

That is a fantastic idea to measure the drop at 300 and adjust the velocity to match. Can you confirm for this exercise...

- Make sure rifle is dead on at 100
-Shoot a round at 300. Lets say 5 rounds.
-Average the 5 rounds and their associated drop. Let's say average is 9.7 inches.
-2400 ABS states 10.3" Drop.
-Adjust Speed in the Sig app until its ballistic solver matches the MOA needed for the 9.7" Drop?

It very well could be a chrono issue. I had come up with an average speed of 3053 utilizing a 5 shot average from a not very good chrono. ( PRO Chrono)

Yes, that is just what you do. That gets you all the velocity data you need to get started.

Believe the bullet when it comes to drop. The problem is when the ruler to measure the angle you are using is off. The angles we are talking about are VERY tiny, mere fractions of a degree, 20 moa is 1/5 of one degree.... so it doesn't take much when the angle measuring device is screwed up.

It probably returns to zero fine, but think of how small the mechanism must be to make an adjustment that fine. A small QC error is all it takes. Many high quality scopes still have a small error in them.