A while back Knights Armament offered an Otterbox iPhone case with flip out rail attachment. They don't seem to offer it anymore for reasons unknown , but it would be way to expensive either way. The TactiCool aspect of this project is high but is it practical? If your outdoor range has Wi-Fi maybe, for in country or deployed , I don't think so.

This is not for running around playing Rambo in the woods its for use at an outdoor range and want easy access to a Ballistics Calculator.

that said this can be built for under $20 ( not including software cost ) where as the original was ? probably over $100!

Step 1: Parts and Supplies

PARTS:
iPhone or iTouch ( Obviously ) I used an old jail broken 3G for this so the case part # will reflect that $?FREE
3G case from DX SKU# 14367 it's tight fitting and has a rubberized coating $2.05
MBUS Magpul Clone sights from DX SKU# 65703 ( but you get front and back sights so potential 2 uses for this) $14.99
Gun sight riser mount from DX SKU# 33821 $3.80
small 90 degree angle stock . can be anything lying around I used a small piece from a laser printer that worked perfectly.

SUPPLIES and TOOLS:
5min Epoxy from HB $1?
ABS to PVC CEMENT $? I had it already
1/2 round file

Step 2: Mount and Mark

I used the front sight because it seemed more tight and less likely to inadvertently flip out due to recoil if not in use.
Mount sight on riser and then slide on rail , flip open sight and adjust to were you would like it for viewing.
THIS WILL USUALLY BE ON THE LEFT SIDE OF THE FOREARM. Your ejection port will be on the right and you don't want hot brass hitting your iPhone!
After you mounted it where you think you want it , put the iPhone case on the sight and adjust for the correct height for viewing.
It helps if you have the Bipod down and are looking though the scope then looking over to the iPhone. You want clearance from the scope as well as any exotic mags you might put in your firearm. Also certain receivers might even require a larger riser or 2 risers together for clearance.
After you have height down. Scribe or mark around the sight on the case.
Fold the sight back with case and iPhone to make sure you have clearance.

Step 3: The Build

Now that you marked where the site attaches
Use the ABS to PVC cement inside the marks. This will remove the rubberized coating. Leave it on for a minute or 2 then scrap it off.
Now remove the the sight post and set screw from the sight
Cut off top of post. Not really necessary but I think it looks better.
Hold the case up to the sight and see where you need to file to contour to the case.
File the inside of the blades so you can put your angle stock in between . I was lucky in that my scrap already had a hole were the sight post would go, if not drill a hole.
I now painted the sight post and angle stock flat black.
I used the cement inside the sight as well but don't think it etched it at all. I am listing it as I did it though.
Mix a little bit of 5 min Epoxy in small container.. It's clear and clear but mix it good it will get opaque.
First put on lower top of sight ( where sight post goes )
put in angle stock
Put in sight post screw and tighten
I made sure everything was flush and then let it sit for a day.
Then mix up more 5 min Epoxy and put on bottom of sight where attachment goes and in the clean area of the case.
Attach and hold tight for 5 minutes.
I then mixed up more epoxy and filled in any places around edge and made button on top of other hole in angle stock for added strength.

Step 4: Thats It! a $20 TactiCool Accessory

Final Notes:
I might build a strip around the sight portion to clean up the lines a bit from the Epoxy.

I am no way saying this is as good or rugged as the KAC version, but they don't even offer it anymore to my knowledge.

I used iSNIPE as the app in the Photos, There are many Ballistic Calculators for iOS and a few for Android as well. I do not know which is best for you and I am not endorsing any Ballistic Calculator over the other.

Sorry there were not more step by step pictures but it was already built before I did the Instructable. It's pretty straight forward if you read the steps.

P.S. I don't hunt or go out of my way to kill animals so whomever decides to use this idea and build their own , It's for OUTDOOR RANGE USE ONLY!