I made this one patterned after the ones that LaRue uses for their rifle test targets, but I made it Mil instead of MOA and increased the number of targets available to shoot.
My Mil Target
I print it on a laser printer with some heavier paper (not card stock, but not standard copy paper.) I usually use an off-white almost peach type color. Works well in most cases.
I went through several versions with diferent shading, closed centers vs open centers. This is the one that worked best for us.