Range Report Shooter Calculated Solution vs Observed

[BamaAl]

Help! I nned some learnin!

I've been using shooter to calculate 1000 yard solutions and what I'm experiencing vs the calcs are a long way apart. I've tweaked everything I know and just can't come up with results that match what is really happening. Shooter says up 28 MOA and I'm consistently seeing 35.5 MOA. Data is below:

Barrel 1:10
308
SMK 175 HPBT
Muzzle velocity 2616
G7
Litz BCs
ASM
Sight height 1"

Everybody has such good results with shooter so it's got to be me setting something up wrong. Any ideas?

Thanks for your help.

 

[WhiskeyWebber]

Re: Shooter Calculated Solution vs Observed

are you sure your atmospherics are correct? Check and make sure your density altitude isn't on some crazy high number.

 

[BamaAl]

Re: Shooter Calculated Solution vs Observed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body">are you sure your atmospherics are correct? Check and make sure your density altitude isn't on some crazy high number. </div></div>

Nope. Not out of the box. 695.

 

[BamaAl]

Re: Shooter Calculated Solution vs Observed

The only way I can get to 35.5 MOA is to drop my muzzle velocity to 2350 and I know I'm getting 2616 because I've used the chrono to measure the loads.

 

[WhiskeyWebber]

Re: Shooter Calculated Solution vs Observed

hmmm... I'm running the same combos and the shooter program and I get 34.3MOA out to 1000 with a MV of 2650. Only thing I can think of is your BC might be too high.

 

[BamaAl]

Re: Shooter Calculated Solution vs Observed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body">hmmm... I'm running the same combos and the shooter program and I get 34.3MOA out to 1000 with a MV of 2650. Only thing I can think of is your BC might be too high. </div></div>

The Litz profiles don't let me change the BCs do they?

 

[BamaAl]

Re: Shooter Calculated Solution vs Observed

Here is the table of all the data inputs. Sorry, i just figured out how to get them all out or I would have put them in the original post. And it 's yielding 28.2 MOA, not 28.

Firearm: Savage 11 Long Range Hunter .308
Barrel Twist 1 in 10.000 in Twist Dir. Right
Sight Height 1.000 in Sight Offset 0.000 in
Elev. CF 1.00000 Wind CF 1.00000
Ammo: Sierra 175gr MatchKing (Litz)
Bullet Diameter 0.308 Bullet Weight 175.00 gr
Bullet Length 1.2400 in Atmos. Std. ASM
Muzzle Vel. 2616.00 fps Vel. Varation 0.00 fps
Drag Model G7 Powder Temp 80 °F
Zero Range 100 yd Zero Height 0.000 in
Zero Offset 0.000 in
Atmosphere
Density Alt. 695.00 ft Temp 79.00 °F
Shot Data
Move Speed 0.00 mph Move Angle 0.00 °
Look Angle 0.00 ° Spin Drift Off
Wind Speed 0.00 mph Wind Angle 0.00 °
Coriolis Effect Off Latitude 0.000 °
Azimuth 0 °

 

[00bullitt]

Re: Shooter Calculated Solution vs Observed

Anytime you are going to reference anything that Litz publishes, you need to reference the ICAO atmospheric standard instead of ASM.

ASM is the way of the dinosaur.

That is going to account for substantial inaccuracy you are seeing.

Also, your sight height is centerline of scope above centerline of bore. Most likely somewhere around 2".

Fix those two items and recalculate.

 

[WhiskeyWebber]

Re: Shooter Calculated Solution vs Observed

Not sure if I can explain this correctly without a video but here goes...

Once you open the program, you pick your gun, then it lists the cartridges you have set up for that gun. If you select your desired cartridge and keep holding it down you'll get screen that pops up that will ask if you want to edit, delete, or duplicate. Click on edit and it will take you to a screen where you can edit everything including BC.

BTW I was getting my numbers using the G1 BC model. Maybe you switched to a G7 model but were still using G1 actuals... that might account for the extra flat trajectory.

 

[BryanLitz]

Re: Shooter Calculated Solution vs Observed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body">BTW I was getting my numbers using the G1 BC model. Maybe you switched to a G7 model but were still using G1 actuals... that might account for the extra flat trajectory. </div></div>

This is my best guess as well.

Try editing the ammo profile as Whiskey explained above, and instead of selecting a bullet from the library, enter .243 for the G7 BC and see if that affects anything.

The error you're seeing is on the order of a G1/G7 mismatch.

 

[BamaAl]

Re: Shooter Calculated Solution vs Observed

Ok, so I created a test ammo with .243 as BC. It got closer. 37.7 MOA. Data entered is below.

Why would the data library be wrong? Maybe it got corrupted somehow? Should I delete the app and reinstall?

Firearm: Savage 11 Long Range Hunter .308
Barrel Twist 1 in 10.000 in Twist Dir. Right
Sight Height 2.000 in Sight Offset 0.000 in
Elev. CF 1.00000 Wind CF 1.00000
Ammo: Test 175
Bullet Diameter 0.308 Bullet Weight 175.00 gr
Bullet Length 1.2400 in Atmos. Std. ICAO
Muzzle Vel. 2616.00 fps Vel. Varation 0.00 fps
Drag Model G7 Powder Temp N/A °F
BC(s) [email protected]
Zero Range 100 yd Zero Height 0.000 in
Zero Offset 0.000 in
Atmosphere
Density Alt. 3112.00 ft Temp 90.00 °F
Shot Data
Move Speed 0.00 mph Move Angle 0.00 °
Look Angle 0.00 ° Spin Drift Off
Wind Speed 5.80 mph Wind Angle 0.00 °
Coriolis Effect Off Latitude 0.000 °
Azimuth 0 °

 

[WhiskeyWebber]

Re: Shooter Calculated Solution vs Observed

I don't think I've heard of the DB getting corrupted before. I did notice that you can opt into the G7 calculation and it will take your G1 number without asking you to change it and vice versa... it's just a little check mark at it will give you either flat "L.A.S.E.R." beams or big loopy parabolas.

 

[Killswitch Engage]

Re: Shooter Calculated Solution vs Observed

looks like to me you had actual asl in your density altitude. i dont know what your asl is but you show nearly 2400ft difference in your first data page to your second with only 11 degrees temp difference. that alone will account for your descrepincy at 1000yd. you have to have good data in to get good data out.

 

[BryanLitz]

Re: Shooter Calculated Solution vs Observed

Now that you're within a couple MOA, my next guess would be to verify your scope turret movement. A correction factor of ~.94 may be in order on the elevation.

Of course atmospherics could be at play as well.

Be sure to understand each and every input, and it's effect. And don't take your scope movement for granted.

Good luck,
-Bryan

 

[Playerz1337]

Re: Shooter Calculated Solution vs Observed

*Bookmarking this thread for a later read.

 

[BamaAl]

Re: Shooter Calculated Solution vs Observed

Thanks very much Bryan. It had not occured to me that my elevation adjustments might not be 1/4 MOA. For what I paid for that (censored high end manufacturer)....I feel so violated!

 

[turbo54]

Re: Shooter Calculated Solution vs Observed

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BamaAl</div><div class="ubbcode-body">Thanks very much Bryan. It had not occured to me that my elevation adjustments might not be 1/4 MOA. For what I paid for that (censored high end manufacturer)....I feel so violated!

</div></div>

I feel ya. My Bender had a tracking issue that took me a year of head-scratching to find, because I just always ASSUMED my $3k scope was good to go.

 

[deersniper]

Re: Shooter Calculated Solution vs Observed

Yousure you're scope is only one inch from center of bore?