Eric,

You wrote:
"...sometimes this would result in a shot very far off from the rest
of the group, other
> times it would be right on...it was about 12 degrees F and I was
shooting with an anschutz "

I shoot with Federal Gold Match most of the time with good results.
My first race at West Yellowstone, the temperature was -4 degrees F.
I could not get a grouping. Lots of penalty loops. And the shooting
is usually the best part of my race! Later I was told the cold
weather (from 15 to 20 degrees F and below), affects the powder in the
bullets.

I tried various "polar" rounds and found 3 types worked out of 5 for
my rifle (Izhmash Biathlon 7-4). Good groupings at -20 degrees F
(Brrrrr!)

Below is part of Allen's website that discusses it.

http://www.biathlon.net/low_temp.html

Have fun and good shooting, John