I have a few questions regarding chronagraphs.

1) How much velocity does a high intensity cartridge (260, 7mm, etc) loose in the 3 meter distance between the muzzle and the chrony?

2) What type of extreme spreads and average deviations are good for big game hunting ammo?

Thanks in advance.

#1. About 10fps. Negligible for your purposes.

#2. An SD of about 20 is acceptable but we all strive for single digits.

1) How much velocity does a high intensity cartridge (260, 7mm, etc) loose in the 3 meter distance between the muzzle and the chrony?

Depends on the bullets BC, but my Oehler 43 manual sayes in ten feet at 3000 fps a BC of .4 looses 9 and 3500 looses 8. A BC of .5 at 3000 is about 7 and 3500 about 6 fps. I was just reading this last night.

2) What type of extreme spreads and average deviations are good for big game hunting ammo?

As small as possible, single didgets if you can.

1 -- The ten feet would be about right in my opinion. 2 -- I strive for single digits. Twice I have recorded a 0 Sum of the differences. Once with a Chrony and once with an Oehler, and with the same rifle. Good shooting.

Thanks for the help. I've been getting some loads in the single digits, so I will keep that in mind.