Is the DM 1K line open on the weekdays?

officially no, but there is a hidden 1k target that would have to be pointed out to you that you can shoot from the main rifle line. If there is nobody else on the range, you can use the 1k pad but if somebody else shows up, you have to give up the line so that the rest of the range can be used. I know that Chris butler used to use the range at dawn almost every day, but he is working now. Send him a PM and see if he can met up with you....

Shooting from the 1k pad to the "hidden" 1K target, you would be shooting 1400 yards
I think the size of the "hidden" 1k target is about 24"-30"ish