Have shot it from around freezing to 90 degrees, no changes. As a matter of fact, shot it today, first time in almost 2 years, still dead on. It was about 55 today, about 85 last time I shot it.
I have heard 209 likes a lot of seating pressure, alot. Before I read that, I could not get any decent groups. I really bear down on it with a range rod now and it makes a huge difference in my gun.
This has been my experience as well. A lot of seating pressure...more than you think is necessary...and my groups shrunk by half.
