New Option For Ballistics Calculator on Android

[pfxn]

Hi All,

Long time reader here, but this is my first post.

For those currently running a ballistics app on their android phone ( free or otherwise ), I just wanted to point out that I've written one that is now available for android. Put a lot of work into this so your feedback (positive or negative) is really appreciated.

As is usual for these sorts of things, I have a free version and paid version.
There are many free options with reduced feature sets, but I'd like to think that none are as nice to use or have as many features as my free version. The main limitations are lack of spin drift, lack of Corliolis corrections, and lack of Monte Carlo (dispersion) analysis.


Every version has "nice" features for a ballistics calculator like the ability to store your rifles and loads, a built in ballistics library with a few hundred projectiles, scope overlays. Scope overlays have correct stadia marking dimensions and thicknesses, they are zoomable using pinch-to-zoom with correct support for first and 2nd focal plane scopes. The scope library is no doubt sparse at the moment but if you put in a request for a scope here I'll do my best to get it in the before your next range trip

You can also do truing of muzzle velocity, even in the free version, to get your drops dead on even at very long ranges.

I tried where possible to add little things that people might find useful. For example if you run a Monte Carlo shot dispersion analysis and your Target is set to an F-Class target, it will run through the shot dispersion and estimate an "average" F-Class score for your setup. It will show that estimate in the solution details (small font area) in the solution tab. Just don't be surprised if your score comes out to something like 188.8-3.6X, that just means for many shots it predicts you'll get within the X ring 3.6 out of 20 times.

I could write more about what it can do, but I think I won't bore you with the details. Thanks for having a look at what I have to offer. Happy shooting.


See below for some screenshots, or just install it to try it out. I'd appreciate feedback and requests if you have any.

Link to Free Version









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Pick a rifle ( long click to edit/copy/delete )








Pick a load (long click to edit/copy/delete)








Here's where you set up your target conditions, like range, atmospheric conditions, etc.







Solution HUD tells you your drop in multiple units, including "clicks" for your rifle's scope. Set the click value of your scope when editing the rifle.









Drop tables









Showing predicted drops (red dots) for a 5.56 pattern rifle to the ACOG drop markers. You'll see in the next image that they match up pretty much correctly, but it's tough to see each drop marker when looking through a 4X scope out to 800 meters.









"overzoom" just means we're scaling the view up larger than the scope will allow. An IPSC target at 800 meters is hard to see otherwise through the ACOG.





Compare trajectories for different rifles/loads








Simulated a bunch of shots from that .223 to an IPSC target at 800 meters






The scope view (from the plot tab go to menu -> Scope View) shows you how to hold assuming you haven't dialed any wind/elevation into your scope.

 

[ThePenguinKnight]

I'll give the free version a download and see how I like it. I've been using the free Streak for years with fine results, but your ballistic graphs and general app layout look promising.

What language(s) did you develop it in? How long did it take to get to this point in development?

Thanks =)

 

[pfxn]

One of my intentions was to have a cleaner interface than Strelok, be simpler to navigate than Shooter ( which I used for a while ), but probably most importantly to add and have control of the features that I wanted (like scope view, shot dispersions, etc.). Some features that those other solvers have though are notably missing from mine at the moment. For example kestrel support over bluetooth ( mail me a kestrel and I'll add it ).

Again, I would really appreciate feedback on ease of use, bugs (I'd guess there are still a few lingering), and feature suggestions.

It's in Java. The solver is a standalone library so that it can be integrated easily on other platforms besides Android. It actually ran first in a Desktop application during development. I've also re-implemented the solver in C++. I've been slowly working on it in some form or another over the past year.

 

[JimKirk]

I probably missed it ... but does it have a Input for sight height?

 

[ThePenguinKnight]

Note that I have no experience with Shooter, but I've used Strelok free and some other free apps, plus regular internet ballistic apps a fair amount.

I got the distinct feeling this app is tailored to long-range shooters, especially because the load page defaults to G7 drag and the current list of reticles/scopes favors long-range or tactical scopes and reticles, and is lacking many common hunting options (3-9x40 duplex reticle of any kind? I guess the 3.5-10 Leupold duplex is close enough). There's nothing wrong with that, and makes complete sense given that most hunters don't need much in the way of ballistic calculations-- just a side-note.

Initial impressions with an afternoon of playing with the app off-and-on (using Galaxy Note 4):

Good points:
- I like the graphs/plots, and the ability to compare loads on the same graph/plot, and the variety of data that can be graphed/plotted
- Clean interface, works well (I’m not a fan of the swipe pages and unlabeled buttons on the header bar in any app, but it follows mobile app convention and is very usable, esp. as compared to Strelok and lesser apps)
- Out-of-the-box import/export functionality even in the free version
- Out-of-the-box scope view
- Scope view mode includes customizable zoom levels, even in free version
- Results closely match other, trusted ballistic calculators (which I admit I’ve only proven to ~400yds)

Needs work:
- Fields are prepopulated, must be cleared before data is entered. Not a huge problem, but using "ghost text" or clearing the field on-focus would be better.
- App crashes and dumps me back to initial screen with an error dialog if adding a non-numeric value to the “Caliber” field on rifle screen (such as .30-06, 277WLV, 308WIN, etc.). Should handle this more gracefully.
- Lacks Nikon BDC reticles (3-9x40 standard BDC for two of my hunting scopes-- this is personal point, clearly might be low-priority for you)
- Scope zoom level should be settable via a field also, as pinch-to-zoom can be difficult to hit specific zoom levels
- Swipe left/right on the “Solution” page can adjust values (range, wind speed) while still moving to the adjacent page if I'm not careful where I'm swiping with my thumb.
- On the Target page, number input dialog doesn’t want to close when field loses focus; the number input box even persists when switching to different pages unless you explicitly hit the “Back” button, or return to the offending page and cycle through all the fields with the “next” button

Extra question:
- Bullet length is a field for the load data, which is generally not a field on other calculators; I assume this field comes to play in spin drift calculations, but does it come into play anywhere else?


I like the app and I'm gonna continue playing with it. Thanks for your efforts on developing it.

 

[taliv]

are you using point mass or pejsa?

 

[pfxn]

JimKirk: Yes. Input the sight height on the page where you edit the rifle.

ThePenguinKnight:

Really appreciate your thoughts. All good points.
Sorry about that crash. I'll fix that ASAP.

I didn't add any Nikon scopes because I don't own any. I can probably add some popular Nikon models this evening, including your 3-9 x 40 BDC. There currently is one "common" hunting optic. The Leupold Mk3 3.5-9X40 with Duplex reticle, as that's what I have on my hunting rifle. I'll be adding more. Scopes are tough because each one is unique, and there are literally thousands. I can usually add one in 10 minutes or so, assuming I have a good description of the dimensions.

I'll add a field to type in zoom level by hand, but it will be a bit on that one. I intend to do this when I add the ability to also have an arbitrary windage/elevation dialed in to the scope view. An example use case being dialing in your elevation and just hold windage.

I'll look into the swipe issue.

About the number input dialog, you actually use that number input dialog differently than I. You know I'eve never cycled through all fields to get it to close, I always just hit back. Didn't even realize it would close that way, just figured it would start looping through fields from the top again. I'll make it explicitly close the number input dialog when changing tabs, unless you have another suggestion.

Yes, bullet length is only used for Spin Drift. It should be hidden when in simple mode, as it's unused in that case. I'll remove it from the interface when in simple mode.

Taliv: It's a point mass solver with a Runge-Kutta integration method.

 

[ThePenguinKnight]

It's a pretty cool app already, can't wait to see it as you iterate.

Any plans to open source? Now you've piqued my interest and I'd love to poke through code from a ballistic calculator. I may look around github later...

One feature that you may consider adding is a view to spell out, for a given zero distance and magnification, what the distances are for each reticle holdover mark.

 

[GarySTL]

I down loaded and installed.

Get error loading weather whenever the app starts

It seemed to pick up my scope, viper PST, from Strelok. Is that right?

 

[pfxn]

Gary: It didn't get the scope from Strelok, I've built that scope in by hand. I'll look into that error. I get it too, sometimes. I think it's a connectivity issue when fetching weather from the weather service. You can turn off weather from internet for now to get rid of it, but then you won't get live weather info.

ThePenguinKnight: Not looking to open source this at the moment. I did add your scope though as consolation, and fixed 2 of the bugs you reported. Thanks. It usually takes a few hours (or a day?) between when I push an update, and that update actually getting to your phone.

 

[CarJunkieLS1]

I'll say this...if your app had a way to add more than one scope correction factor every single long range shooter I know would be using it.

 

[pfxn]

What do you mean by "more than one" scope correction factor?

I'm assuming this means you did a tracking test and decided for example at 10 MOA you needed a correction factor of X, but at 20 MOA you needed a correction factor of Y. Yes?

 

[CarJunkieLS1]

Pfxn yes you are absolutely correct. That is exactly what I meant. For example my long range shooting rig...at 500 yards needs a scope correction of 1.1% meaning if I dial 3.4mils my scope has actually move 0.34 mils less than I actually dialed. But at 1000 yards I have a scope correction of 1.4%.

So without having more than one scope correction factor people are having to go in and adjust their velocity or B.C. at very specific distances just to correct for mechanical error in the scope.

 

[pfxn]

I'll think about that CarJunkie, it's not my top priority right now, but it could be done without much issue.

Just made another update. First, I fixed that weather issue. I've also added the ability to edit custom drag curves though, so you guys can now set the drag to custom and put in more accurate drag curves (assuming you can get curves for your particular bullet). For example Lapua has done some live fire doppler radar measurements, and they have posted (at least some?) data here. You want to follow the "Download drag tables zip file" link. Entering all that data by hand is tedious, I know, but you'll only have to do it once for your load.


This is what entering custom curves looks like. Just edit your load, and change drag reference to "Custom". Add or remove rows with +/- buttons.




I've also added the ability to calculate the effect of cant error (rifle rotated slightly left/right) on shot dispersion in the paid version. I don't know of anyone else who is doing this type of calculation, but they should be.