You can make your set anytime. But Early to mid morning and the evening to nighttime are the best IMHO. Make sure the wind is in your favor..

BTW. Why would you have a 6X24 on a .17HMR.. Thats pretty odd. You don't even need a 6X24 on a .22/250 unless it is a Extremely expensive scope, it will blur before you get to 15-18.. Just wondering. anyway, good luck. The boombox is primative but will work..

DuB