Real world drops and Shooter app vastly different. 6.5 Saum, 156 EOL Bergers, RL26

pwrdbycotn

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Joined
Dec 15, 2010
Messages
552
Today I took my 6.5 saum out to get ready for deer season. Since last season I have changed scopes (Tangent Theta 315P) and decided to switch to the 156gr EOL bullets.
I am loading 58 gr RL-26, 215M, ADG brass with no signs of pressure.
According to my labradar, my speeds were as follows: 2990, 3014, 3018, 3022, 3018, 3022, 3025, 3024, 3030, 3025, 3026, 3027, 3021, 3025, 3032, 3024, 3038, 3014, 3021, 3034, 3040, 3027, 3040, 3037, 3052
Rounds were left in the sun in the ammo box, which is why the speeds climbed some over the course of 2.5 hrs.
The gun wears a suppressor made by Hog Rush.
This load shoots very well accuracy-wise.

Here’s the issue:
My shooting confirmed my drops as follows
200 yd- zero
400 yd- 5.25 moa
600 yd- 11.25
800 yd- 16.25
The shooter app calls for:
400 yd- 3.0
600 yd- 8.0
800 yd- 13.8

Why is there such a big difference? I’ve used the Shooter app for years and while there has always been a slight discrepancy between the real world and the app, it has always been minor and I’ve been able to make everything match up with minor velocity adjustments in the app.
Scope tracking shows to be spot on, and I am making certain there are no canting issues.
I plan to shoot again before season just to verify drops again.

Edit to add: 350 ft ASL, 31% humidity today, 68*
Gun is custom built by Pierce Engineering, 26” Brux, Pierce ti action, Manners, Jewell, Atlas bipod,

What gives?
 
Last edited:

pawater

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Joined
Dec 18, 2012
Messages
997
Any wind involved? Did you run the labradar while confirming? I've seen weird things when the barrel is screaming I want cleaned. Some more often than others. I haven't shot much rl26 to know the characteristics.
 

pwrdbycotn

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Joined
Dec 15, 2010
Messages
552
In the velocity calibration, it tries to say true velocity is 2760. If I change that in the bullet edit, it still calls for less drop than I experienced today.
 

whatnext

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LRH Team Member
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May 24, 2019
Messages
173
Location
Idaho
Go here and enter actual drops. Your trying to resolve a ballistic curve by guessing at the velocity which may not be the issue. It could be environmental or BC.
 

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whatnext

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Messages
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Location
Idaho
The more real drops you enter the better it can resolve the curve. I will say this, I don’t like it because garbage in -garbage out. I’ve experienced the same problem but when you can’t identify the error, it’s the next best thing I know to do. Just be sure to enter drops sequentially from short to long
 
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