Sometimes the lower sun angle during winter seems to cause some variations in the neighborhood of 50 fps or more on some identical loads with my Pro-Chrono. Just a thought. At my range I shoot from West to East. My chronograph sometimes quits working about 2:00 pm due to the sun angle.

I have not noticed any velocity difference due to DBC.

Last edited by nifty-two-fifty; 02/27/15.
Nifty-250

"If you don't know where you're going, you may wind up somewhere else".
Yogi Berra