I was wondering what would be the best factory load for crows out to 40 yards?

If you hunt crows in very cold weather most any 20 field loads from 1- 1-1/4oz #6 or #7-1/7oz will loose as much as 40% efficiency. In warm weather 1oz loads will do fine with above shot sizes out to 40 yrds. AT present Ballistic Products is sending me some loads with Herco for the 20. A couple of weeks ago we were out for released phesants close to 0 F 15C my 20 did not perform very well. But maybe I was froze stiff. It is best to switch to the HV 12's when it gets cold.
Fred M.