Here is a target sled.
(2) 2 x 4 Sled rails cut to the length you want.
(2) 2 x 4 cross members cut to the width you want.
(2) Pieces of ½” all thread cut to the length that you want.
(4) Flat washers
(4) Nuts
Cut an angle in at one end of the two boards that will be the sled’s rails and drill a hole in the end above the angles.
Drill a ½” hole in each of the cross members.
Fasten the cross members to the sled rails.
Put a nut and a washer on each of the all threads about 2.5” up.
Pass the all thread through the cross members.
Put a washer and nut on the under side of the cross member and tighten.
Tie a rope through the holes in the target sled.