Ballistics help please

[LuckySeven]

Anybody have a program to calculate actual muzzle velocity ????
Ran some loads from my 7RUM through the chrony...3204 fps 10 feet from the muzzle...so what would be the actual velocity at the muzzle ???

[Dick284]

In 10 feet your likely going to have a velocity change withing the normal Standard Deviation of the load.
Call it 3210 and go from there.

[LuckySeven]

92 grains of Retumbo gave me 3202,3204,3204 for 3 rounds........I'm liking the SD on this load !!!

1 " thick plate steel at 500yds finally stopped the Bergers

[Dick284]

Originally Posted by LuckySeven

92 grains of Retumbo gave me 3202,3204,3204 for 3 rounds........I'm liking the SD on this load !!!

1 " thick plate steel at 500yds finally stopped the Bergers

Looks good how's it do on a 10 round string.
A satstistician would bust a gut on a founding of 3 shots.
Looks good from my chair mind you.
Still work it for 3210fps.

[sbtennex]

Originally Posted by LuckySeven

Anybody have a program to calculate actual muzzle velocity ????
Ran some loads from my 7RUM through the chrony...3204 fps 10 feet from the muzzle...so what would be the actual velocity at the muzzle ???

No. And for any real purposes what's the difference? Standard published vel's are about 10 ft from the muzzle for measurement capability purposes. Deviations are just that in groups, and by the laws of physics there is no way to accurately determine the MV - there are far too many variables, most of them relating to the actual load dynamics. Truth is, the MV can be quite easily less than the chrono'd velocity 10 ft from the muzzle.

[LuckySeven]

I'll have a better idea of the (real) SD tomorrow when I start firing for groups based on seating depths. I was just working on hitting the 3200 fps velocity right now. 21 rounds loaded and ready to go first thing in the morning....Hmmmm, hope the neighbors hadn't planned on sleeping to late !!!!
For all intents and purposes I was just looking for some comparison to some tables I printed off at work for elev drops to convert into M.O.A. when I start banging the gongs out at 1000 YDS.

[AB2506]

WHO CARES?

The difference, from the muzzle to 10 ft away is statistically insignificant. The atmospheric conditions could have a bigger affect on your calculations than the difference between the velocities over a measly 10 ft.

Run with your chrony numbers at 10 ft an don't worry about it.