SDs and ESs with .308 & .243

I utilized the Lab Radar (earlier post) to log the velocities of my .308 and .243 rifles today.  I did this so that I could put that information into an app and calculate hold-overs at greater distances.  This also allowed me the opportunity to sight all my rifles in at 100 yards and set the zero stops.

So what did I learn?  Well I shot Federal Match ammo out of the .308.  It was 168 grain boat-tail hollow point bullets.  The stated velocity from the Lab Radar was 2,758 feet / second (840 m/s).  What was impressive was that for 9 shots, the Standard Deviation (SD) was 8 fps and the Extreme Spread was 24 fps - from a Factory Load!  That is some pretty nice work there Federal!

The hand loads for my .243 were not quite as impressive.  The SD was 25 fps and the ES was 76 fps.  However, I logged a 0.80" group with this load.  The .308 4-shot group landed at 1.46" - both groups at 100 yards.  3 shots from the .308 landed within 0.75" - I just had that one flier.  I will admit though, I had quite a few rounds thru the barrel and it was warming up quickly. 

Shout out to AccurateShooter.com for publishing printable targets to log all this data.  Here is the one I used and also referenced in my earlier post about the Sig BDX.  It's free to download and print from Accurate Shooter.



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