Originally Posted by ven
Went to the range early this morning to do a bit of practice in preparation for a good winter of long range hunting.
After a quick 100 yard zero check that was bang on i placed targerts out to 5oo yards.
All my rounds hit 0.2 mils lower than when i made my drop chart up 4 months ago.Two clicks up put me dead on.
Now when i made my drop chart the temp was 15 c.this morning it was -2 c could this the cause of my low shots.
YEP!!!....I checked my infinity program:105 berger @3050. Drop from 65 F to 28 F gives you 1 additinal inch of drop at 500.
Now, to be honest, not sure exactly what a "mil" is. I am a "MOA" kind of guy.
Also, and mayby a bigger factor, is that MOST of the time (depending on the powder used) you velosity will be LESS when it is cold. Compare you loads with a chrono at the two different extremes. Velosity loss at cold temps is probably your biggest problem.
Hope that helps.