Truing Ballistic Apps

For those LR/PRS shooters out there who use a ballistic app, How do you go about truing your app? I've always gone about it by truing the MV, but I find that the app doesn't match my real world drops. I trued my app at 450 yards first, then I moved out to 800 yards and trued again. But I find that it doesn't match up if I move to a different location.

I use Strelok Pro, but I'm wondering what others are using and how you go about your truing procedure.

I want to have it correct, so that when I go up in Altitude that the app will be able to correct for the difference in altitude, pressure, and drop. I don't want to have to true my drops everywhere I go.

Just read a post on another site that says I should true my MV out to 500 yards and the true the BC at 700-800 yards. The statement implied that if I do it that way, then my drops will be correct no matter where I shoot.

What do you all do? And does your app match up to your yardages between 100 and 1000 yards?

Thanks,

I am in the same boat as you. I have some loads that seem to line up perfectly, and others that bewilder me. I shoot Hornady ELD-M bullets and have been using the multi-BC data entry. My 140gr 6.5 Creedmoore rounds are all over the map so far. I will reply if/when I figure it out...

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Originally Posted by celltech

I am in the same boat as you. I have some loads that seem to line up perfectly, and others that bewilder me. I shoot Hornady ELD-M bullets and have been using the multi-BC data entry. My 140gr 6.5 Creedmoore rounds are all over the map so far. I will reply if/when I figure it out...

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Thanks Celltech... I will do the same if I can figure it out. I shoot the 143 ELD-X myself. I've never messed with the multi-BC part as I don't understand it. I'm going to try the procedure I just read about on the other site, and true MV out to 450 and then the BC at 700-800 yards and see if it trues up better. I know it won't be and isn't supposed to be "perfect" every time, but it should be getting me on steel/paper more consistently. The other thing I read about, was that one should never true drops when you have mirage... Little tough to do right now....

Using the MultiBC is not hard. Go the the cartridge page, select G7 drag function, hit the multiBC button and enter the values from the Hornady site: https://www.hornady.com/support/ballistic-coefficient

For the 143 ELD-X the BC figures on the left are: .314, .303, .294
These will go against the 3 speed levels: 2512, 2232, 1953

In effect the bullet is more efficient at higher speeds and Strelok will adjust as it figures out how much it slows down over longer ranges...

Thanks for the quick lesson Celltech. I'll give that a try next time I can get out to my LR spot.

Use G7 BC values whenever possible and make sure your sight height is correct. Factory default for most apps is 1.5" and more often than not it is closer to 1.8-2.00" especially if using a rail and 50mm objective scope. If you have an accurate velocity that will usually put you spot on. If further truing is needed you may need to do a tall target test to verify that your click adjustments are actually moving the distance they say they should. If they are not there should be an elevation correction factor that is usually set at 1.0 that may need some adjusting to correlate to what your scope is actually doing. Hope that makes sense.

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Originally Posted by stomp442

Use G7 BC values whenever possible and make sure your sight height is correct. Factory default for most apps is 1.5" and more often than not it is closer to 1.8-2.00" especially if using a rail and 50mm objective scope. If you have an accurate velocity that will usually put you spot on. If further truing is needed you may need to do a tall target test to verify that your click adjustments are actually moving the distance they say they should. If they are not there should be an elevation correction factor that is usually set at 1.0 that may need some adjusting to correlate to what your scope is actually doing. Hope that makes sense.

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Stomp, I do use G7 value of .314 and I have measured my scope height and it's 2.12 inches from center bore to center optic Using a Sightron SIII 6-24x50 FFP. I've trued it before and really there only seems to be a couple clicks difference when I'm off. But its still off. I haven't ever done the tall target test. The last time I tried to true my drop I had heavy mirage and I was 2 clicks low. When I trued that, it dropped my MV down to 2730 FPS from the 2760 FPS that I trued before. I've updated my app to the Multi BC that Celltech provided above, so maybe that will fix my issue. Next Saturday, I'm headed down the the local 200 yard range to zero the 30-06 for Elk season, and I'll get a new MV value (chronograph) for the 06 and the .260.

Thanks for the info, I can use all that I can get.

What Chrony are you using? If you are using a magneto or labradar I would say to leave your velocity alone. In all honesty though if you are within two clicks I would say the app has done its job. There is no way of calculating particular conditions at any given time. Thermals, terrain and up draft or even a parallax issue can easily account for 2 clicks off. I use an app to get me close then I fine tune and record my real world actual shot data.

The Chronograph is one of the older versions of proshooter I believe. It's not a lab radar or magneto speed so I know that it's NOT my exact muzzle velocity, but it's good "ballpark" to start from. I figure I'll start over with a fresh zero confirmation and MV. Then true my app @ 450 yards with MV first (dead center last time gave me a MV of 2760 FPS). and then see what happens at 700-800 yards. I'm hoping it will true up a bit better, now that I have the MultiBC numbers from Celltech. I'll post back my results once I can shoot LR again. Everything is on fire around me right now. You guys have been very helpful with the information I was missing.

I just need to get it entered correctly, so when I move from sea level to 6000-7000 ft. That my drops are more accurately called. Took a shot at a rock across a canyon last year (last day of season) at 675 yards. and my impact was 6-8 inches high (1-2 clicks high). My LR spot is only about 1100 ft. and I had trued my drop to 822 yards before I left using MV to true that drop. That would have been a miss on a deer size target. I need to shrink that down to 3-4 inches hopefully. There wasn't much wind that day, maybe 3-4 mph. I had also taken into account my current atmospheric conditions from my Kestrel (Not the 5700, just one of the cheaper ones, that has temp, barometric, and wind speed/chill).

Thanks again, I appreciate the information and help.

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Originally Posted by SageRat Shooter

The Chronograph is one of the older versions of proshooter I believe. It's not a lab radar or magneto speed so I know that it's NOT my exact muzzle velocity, but it's good "ballpark" to start from. I figure I'll start over with a fresh zero confirmation and MV. Then true my app @ 450 yards with MV first (dead center last time gave me a MV of 2760 FPS). and then see what happens at 700-800 yards. I'm hoping it will true up a bit better, now that I have the MultiBC numbers from Celltech. I'll post back my results once I can shoot LR again. Everything is on fire around me right now. You guys have been very helpful with the information I was missing.

I just need to get it entered correctly, so when I move from sea level to 6000-7000 ft. That my drops are more accurately called. Took a shot at a rock across a canyon last year (last day of season) at 675 yards. and my impact was 6-8 inches high (1-2 clicks high). My LR spot is only about 1100 ft. and I had trued my drop to 822 yards before I left using MV to true that drop. That would have been a miss on a deer size target. I need to shrink that down to 3-4 inches hopefully. There wasn't much wind that day, maybe 3-4 mph. I had also taken into account my current atmospheric conditions from my Kestrel (Not the 5700, just one of the cheaper ones, that has temp, barometric, and wind speed/chill).

Thanks again, I appreciate the information and help.

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Fact is that try as we may, the world isnt perfect, and neither is the data we use.
Stomp has been doing this long enough to realize that.
He has cited several things that could cause a shot to be off target enough for a miss.
There could be others including shooter error, especially when shooting at a live target.
Also realize that conditions can change very quickly, even from what it was since your last shot.
When hunting especially, a spotter using optics like Stomp has for calling shots is very essential.
Especially at the longer distances, and even when hunting, a sighter shot is a good idea.
Actually a first round miss ends up being a sighter shot anyway.
Another good idea is to use cartridges that drive the heavier bullets over 3000 fps.
We dont use a program at all, other than initially for establishing a click chart which we verify by actual shooting.
We use an average for elevation, temp. etc. for the area. The chart is either taped on the gun or stored in the ammo box and dosent change unless we change the load for some reason.
Other than pictures, ive never seen a Kestrel, nor do i know anyone who uses one, and i do know many who hunt L/R.
Most of our shots fall into the 600 to 1000 yd range, with a few over or under those distances.
At least where we hunt, the many tree branches could also cause a miss, and what difference does it make as to what caused it, its still a miss.
Again, a spotter using good optics will as a rule see that.
We are more concerned over how well we shoot, and how fast and accuratly we can follow up with another shot.

That's what I am eventually looking for, but I want to have a repeatable drop chart.... if at all possible. When I go to my LR range and shoot and true, I'd expect my drop to be the same every time I go... Wind is another thing all together. The problem or confusion I'm seeing is that my drop changes every time. Same load, same bullet, same elevation, but my drop changes by 2 clicks. Sometimes 2 clicks high, sometimes 2 clicks low. I'd just like to be able to find a consistent drop chart for that rifle. I'm sure part of it is me, the shooter, but I try my best to remember the fundamentals. I can go 100% @ 450 yards from a cold bore, but I stretch it out to 600 yards or further, and it just goes to hell. That's what I want to fix or figure out what I'm doing wrong. I probably won't ever shoot at an animal over 500 yards, but I'd like to know that I can shoot further consistently. My target is only 10" diameter, so a click or 2 makes a difference in the hit vs miss.

Well id say your chart actually is repeatable, but nothing else is, and is whatever it is, so just deal with the whatever it is part.
If you can make first round hits on milk jug size targets (most of the time), be happy.
And if you cant id be looking at your shooting method rather than blaming the chart.

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Originally Posted by yobuck

Well id say your chart actually is repeatable, but nothing else is,

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Never seen a truer statement !! There's a reason we shoot sighters.

I was testing powder yesterday. Last week on a good calm, cool, low
humidity day My Lab was telling me 2807 with single digit ES and SD's.
I took the same out yesterday on what seemed to be repeatable
conditions, and I was at 2819 with the ES hitting 14. Both were 10 shot
strings, and from the same load cycle batch. I figured one or two of my
loads were slight off. Normally I will blame neck tension. Either way, If
your going to shoot long, load extra for the moment.....