Questions about What I'am doing wrong!!

[Warren Wallace]

300 rum, 93 grs. of retumbo, 220 gr. smk, 3155 fps consistent. recon spits out drop table and it is consistently wrong until I change my scope over bore to 3.5 then it is dead on! I know I'am doing something wrong but have no Idea what, gun is very accurate as long as I change that measurement

 

[Mikecr]

What BC are you using?
How are you setting local atmospheric conditions?
What are your scope clicks equal to?
How are you coming to the conclusion that actual drop is not as high as it should be?

 

[Warren Wallace]

factory bc of .648, brunton weather station, leopold mk4 clicks 1/4 i think! when I set it at 1.5 i hit very high

 

[Warren Wallace]

this is relayed info for my buddies gun 30 inch lilja on a mark 5. my gun is not built yet just got the action!

 

[Mikecr]

OK we're gettin there. Can you remember the actual shooting conditions?
What is 'Recon'?

The Mk4s are 1/4moa clicks.. Your sea level standard BC is close..
I wonder if your ballistic software is actually using the local conditions entered..
If not, this would account for hitting high across the board, because your local BC is probably quite a bit higher.

 

[Warren Wallace]

recon is the ballistic computer that nightforce seels with there program on it. the conditions were entered in the computer. I have heard about having to adjust your bc to get your drop charts to match what is the procedure for figuring this out. How do you figure your actual bc without being a rocket scientist!!

 

[Mikecr]

Ballistic software adjusts SL Std BC to 'local' BC for you. Or atleast, it should.
If you can tell me your shooting conditions(those entered), I can figure local BC and using it may reflect the drop seen.
This might help with ruling out a program/entry issue.

 

[Warren Wallace]

temp was 78 humidity was 48, baro pressure was 26.88, altitude was 2400, velocity was 3155 at muzzle, 3023 at 100 yards, 220 smk

 

[Mikecr]

I figure a local BC of .754 with 78deg/46%/26.88"/3150mv
Actual altitude doesn't matter.

Run the numbers through your software using G1BC=.754, under SL Std conditions(default).
See how it compares to what you were getting in the field.

 

[Warren Wallace]

learned more fromnightforce today, apparently reading the directions pay off. they have a trajectory valedation function where you shoot at 3, 4, and 5 hundred yards and enter it in and the computer will adjust. now i don't know if it adjusts the bc or what but hey were making progress.