Evaluate my. 260 results

[codemancode]

New to the .260 scene so i'll break down my rig and issue as simply as possible.

Gun: Savage Model 12 LRP, 26" barrel

Optic: Vortex Viper PST 6x25x50

Load:
Virgin Lapua
45.0 grains H4831
CCI Large Rifle
140 Nosler Custom Comp

Conditions:
80 degrees
1500 ft altitude
no wind
very slight downward angle to target

This load shot excellent groups (.5 MOA) at 100 during zeroing. Pushed back to 650 yards (farthest i can go this time of year) and took a wild stab at the muzzle velocity just to true the trajectory. I guessed 2700 which put me at 12.3 MOA so i dialed 12.25. Shot a excellent five shot group given the crummy rest (about 1 MOA center to center), but 3.5 MOA low. When I adjust velocity in my ballistic calculator to achieve the correct hold over i'm only around 2450 fps. Could this load really be that slow or is something else going on? Switching to H4350 when the opportunity arrives, but probably wont be for some time.

Thanks

 

[anthonylapoint]

My ballistic calculator, istrelok, comes up with 15.5 MOA drop at 650 yards at 2700 fps. What calculator are you using?

 

[anthonylapoint]

Another is coming up with almost 16 MOA. I would double check your info you put into it. This is just loose guessing too I'm calculating.

Bc=.529
Mv=2700
Scope height=2"
Weather=what you said
Zero=100 yards

Also, density altitude works great. Tells you what the air feels like instead of what you're actually at.

 

[BoilerUP]

Running through Shooter app using the Litz G7 (0.281) for the 140 CC, 1500' altitude, 80F temp, 29.92Hg, 0% RH...I get 15.8 MOA @ 650 yards.

Sounds like your 2700fps guesstimate was right on...

 

[The Lawn Ranger]

If you have the opportunity, I would now confirm your dope at 300 and 1000 yds.

For giggles I like to fine tune at 600 on clay pigeons.

 

[codemancode]

iSnipe, which turned out to be the issue. All inputs were correct; however, when entering the 140 Grain Custom Comp round it auto-populated the G7 ballistic coefficient with the word "Litz" No value was present so i just assumed it was correct. It turns out that the auto-populated value was an error of some sort because the BC was greatly exaggerated. I switched to G1 and manually populated .529 and the calculated trajectory at 650 yards was almost perfect. My trued muzzle velocity is 2720 at 652 yards. Thanks to all for helping me think through this one.