Thread: CDS/Chrono Question

I borrowed an old style shoot-through chronograph to measure the speed of some Sako 165gr Gamehead out of my 18” .308 Kimber Montana, in prep for sending in a Leupold CDS form for a new VX5 3-15.

First shot, w/cold barrel and tape over the suppressor, etc. was 2484 fps. Second shot was 2539 fps. Third was 2544 fps. Rain started to pick up so I packed it up. Bullets grouped very well, sub moa at 100m.

Barrel had been cleaned with five pulls of a bore snake prior to shooting, and a proper clean with rod and patches about 25 shots before that.

I’d be very curious to know what anyone’s thoughts are on the speed I should put on the form. I realise that I probably should have shot more but as I mentioned it was getting wet (and a borrowed chrono).

My thought would be just go with the first, cold shot as that’s usually the one that counts, but I don’t want any follow up shots to go high, either. Maybe 2500 or 2510 fps? Is there much difference in drop at say 300m with 2500 vs 2540 muzzle velocity?

Btw, speed on the box is 2674fps.

Thanks in advance