Ballistic Apps

Buttermilk, are you hot-rodding the load and actually getting 3273 fps like the 2 chrono's are saying? That would explain it. It's also very dangerous ground to walk on.
 
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Buttermilk said:
I'll check this out. Might explain my issue. For my example I posted, this would be off considerably at 0.82. Seems likely that too much, if I'm understanding this feature correctly. (Assuming it's for correctly the scopes adjustment values - in this case the actual adjustment value would be 0.2132 MOA which is possible I suppose but seems excessive).
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As someone said earlier, do a tall target test at 100 yards get your zero exactly perfect, then dial up 30 minutes and measure. adjust your scope settings until you get exactly 30 minutes now your scope is True, go back to the range and see what are the results? The setting is very sensitive. You may use .01 or .001 adjustments.
 
JTH said:
Tagging in, I'm interested to learn if you figure this out. If it's 0.7 moa off at 400 that's nearly 3", with that much error it's hard to comprehend that it's just one data entry in a ballistics app, seems like there has to be more going on.
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Yep and I think a few have offered off line help to deal with app input errors. 90% of the time this is what I see with impacts not landing where they should.
 
Buttermilk said:
Currently I use Shooter and Hornady 4DOF.

When both are fed the same inputs, they both put out the same data.

Recently, I've found a place to shoot ~400-420 yds or so. My guns are zero'd at 100 yds.

What I've noticed is that I am repeatedly impacting high on the target after dialing up. Typically 1/2 to 1 MOA difference in impact vs dialed. As an example, my Shooter app may say to dial up 5.5 MOA but actually 4.5 MOA gets the bullet close to point of aim.

So far, everything we've shot (myself, my brother and a friend) have all been high on impact. The closest one yet was my 30 Nosler #1, which impacted only 2" high at 406 yds.

This includes a 6mm ARC, 300 RUM, 30 Nosler, 300 WM, 28 Nosler.

My brother's 300 RUM was calling for 4.5 MOA up. Reality was it only needed 4 MOA up.

The 6mm ARC was calling for 5.5 MOA up, but only needed 5 MOA.

A 300 Win Mag called for 5.5 MOA up but only needed 4.5 MOA up.

I've looked closing at my data inputs, and scratching my head as to why. Everything seems correct. Conditions are input correctly, Gun specifics are correct, load fps is as accurate as my Chrony can be.

I even make sure my actual zero is input correctly as well, as both Shooter & H4DOF allow that.

I'm certain I'm doing something wrong, just not sure what. 🤷‍♂️

If I do the velocity calibration for the 300 WM for example, it says I'm pushing a Berger 190 VLDH at 3273 fps which is insane. Chrony shows 3093 fps average for the load from a 26" barrel.

At 400 yds it's still off a bit, and at farther distances would only get worse.
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On all the ones I have used I have to set it for density altitude and true my rifle at 300 to 600 yards after that I'm good
Geo Ballistic and Kestrel
There is difference between what the chronograph says and what it's actually doing
Ohler chronograph
 
JustMe2 said:
Your "kinda, sorta that number" is because BC changes constantly with velocity changing during flight. BC is based on the velocity of the bullet, shape of the bullet and weight. So, what is the average velocity? Depends on how far away your target is. If you're shooting at 500 yards, your average BC will be different than if your target is averaged over 1000 yards with the same bullet/cartridge because your bullet is slowing down more over 1000 yards than over 500 yards thus changing the average BC value. This is why most ballistics apps ask you what the BC or velocity is at multiple distances to better calibrate the app.
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I am having a hard time following this. I realize that the bullet is losing velocity from the start. I figure a long time ago that the BC maybe better or worst than what was stated. By changing my BC on app did correct the impack of the bullet at different yardages. Which match where I was hitting on the target. I guess you are using the app. to determine the velocity at different ranges. That what throwing me. I don't see how you are getting the velocities at different ranges other than by the app. I do agree that shooting those different ranges and placing input on card works for me.
I didn't use these app for a long time, because I didnt need them for what I was doing. It was simple I held my shoots to 500yds or under, and all my rifles were withing 100fps of each other. So in 500yds it didn't make much difference. The other is I changed to bow hunting for several years. I hug up my rifles. Gettting older, and so I am having to change my ways again.
So I am still learning at 75. I have found it very interesting on how things changed over the years. The use of the app are where I am short on. I have the app, range finders, and Kestrel equipment. Being an old fart dosen't help either.
 
Mike Matteson said:
I am having a hard time following this. I realize that the bullet is losing velocity from the start. I figure a long time ago that the BC maybe better or worst than what was stated. By changing my BC on app did correct the impack of the bullet at different yardages. Which match where I was hitting on the target. I guess you are using the app. to determine the velocity at different ranges. That what throwing me. I don't see how you are getting the velocities at different ranges other than by the app. I do agree that shooting those different ranges and placing input on card works for me.
I didn't use these app for a long time, because I didnt need them for what I was doing. It was simple I held my shoots to 500yds or under, and all my rifles were withing 100fps of each other. So in 500yds it didn't make much difference. The other is I changed to bow hunting for several years. I hug up my rifles. Gettting older, and so I am having to change my ways again.
So I am still learning at 75. I have found it very interesting on how things changed over the years. The use of the app are where I am short on. I have the app, range finders, and Kestrel equipment. Being an old fart dosen't help either.
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The fps drop over the range is a bracket and estimated on the app or from radar. For example hornady and sierra use stepped bc based on velocity ranges you can input it the app. Litz sells a CDM for specific bullets you can input the app. He uses radar to determine fps ranges and BC calculations for the user so you don't have to, only down fall, it cost money. Otherwise, Berger uses an average BC number over the course of range, 1 BC value, and it generally works very well for inside 1000 yards.
 
Mike I was just trying to explain that BC is a moving target and the single BC number listed on ammo and bullet boxes is an average value that the manuf based on assumptions (educated guesses) and sometimes needs to be adjusted for your application. Of course the manuf is going to list the best possible guess as that sells more.
 

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