Range Report Chrono and Balistic App Issue

[aviumvenator]

I recently developed a load for my rifle (specs below) using 2000 MR. I built a profile for the load and rifle in the Shooter app. On an 85 degree day I zeroed at 100 yards and chronoed at 10 feet at 2620 fps. I wanted to calibrate the profile so I set a target at 300 yards. The app recommended U1.3 however I needed U1.5 to have impact at POA and the calculated mv was 2540. I did the same thing on a 70 degree day at 240 yards and the app recommended U.8 however I had to adjust U 1.3 to get impact at POA. The app calculated mv using the U1.3 is 2310 fps. Temperature for the different days was between 70-85.

I use data supplied by the chrono and Shooter app for a .223 and 6.5 grendel AR's and the app recommended corrections work. I even refired some known loads and the chrono was consistent.

I will try a different chrono and try to calibrate at longer ranges. Are there other variables I should look at to get more accurate corrections?

Savage 10 PC .308 20" 5R 11.25 twist
175 SMK
46.5 2000MR
Fed 210M
LC LR brass
2.8 OAL
2620 fps at 85 degrees
Templar Tactical Ark 30 suppressor
12x SS SWFA, Harris bipod, rear bag

 

[DocUSMCRetired]

Are you basing everything solely on Temp, or on Density Altitude?

 

[aviumvenator]

Under Atmosphere chart Density Altitude, Temp, Wind Speed, and Wind Angle all populate after I select Atmosphere from Station. It is on an iPhone.

 

[DocUSMCRetired]

Where are you getting your weather from? I know the weather at weather stations can be drastically different from my actual location.

 

[aviumvenator]

I am using the Atmosphere from station function. I am not sure what station they are using. There is an airport that has a guard base 15 miles away.

 

[_Windrider_]

I am using the Atmosphere from station function. I am not sure what station they are using. There is an airport that has a guard base 15 miles away.

That's your problem right there. You have no idea where the data is coming from. Do you use a kestrel?


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[aviumvenator]

I do not currently have a kestrel but I see one in my future.

Thanks to both of you for the replies.

 

[_Windrider_]

I do not currently have a kestrel but I see one in my future.

Thanks to both of you for the replies.

It's a good investment.


Posted via Tapatalk HD for iPad

 

[Assault116]

Also did you measure your scope height in relation to the bore and input it when you set up the rifle profile? That's one thing that, especially in relatively closer ranges can make a pretty significant difference.

 

[leadbullet]

make sure you have exactly 100 yds zero, i ran into some serious hair pulling situation because my range said it was 100 but in fact was 95, once that was corrected in the app, everything is within 1 click with no weather input included. I threw my chrono away and just work off the app now.
cheers.

 

[TRAAV]

Im not sure that the conditions input would have you messed up at 2 and 300 yards. It sounds like you have something else inputed wrong.