Thread: Ballistic Calc Help

Originally Posted by ebf

Some more thoughts...

From memory, and this is going back at least 5 years - the 300m at Seddon is really only used for a couple of weekends in Jan. The rest of the time they use 300 YARDS.

Please ignore the MV on the electronic target. You are wasting your time thinking this is accurate. It is a mathematical calc using an extremely short distance (couple of inches on the microphone stalk), and does not account for the entry angle of the trajectory.

Looking at the Litz / Applied Ballistics book, your 162gr SST has the following BC:

G1 : 0.535
G7 : 0.274

I also see that your zero atmospherics and those for when you are shooting are the same. Did you record actual atmospherics when you zeroed ?

Hi ebf - thanks for the info.

The 300 m vs yards would help explain it but there was a bit of chat about it on the day and we were definitely shooting 300m. Have redone the inputs heaps of times and used a few different apps and online calculators and my calculation zero is definitely set to 100m not yards. I didn't record actual atmospherics when zeroing, unfortunately.

100% agree that my scope height is not 3 inches. That was the only input adjustment that got me to 3MOA @ 300m, definitely not ideal but am hesitant to change MV to 3300 fsp to arrive at 3 MOA @ 300m.

Thanks for the G7 figure. Hornady doesn't publish a G7 so didn't have a reliable source. Changing it from .550 G1 to .274 G7 still gives me a solution of 3.98MOA @ 300m

Am wondering if the scope wasn't mounted correctly and that has something to do with it.