Well, I grabbed my .177 break barrel air gun and took my grandson to Killdeer to teach him how to shoot safely.
The map in a posting above pin-pointed the location to be about the middle of the dam on the East side. We parked just North of the fence blocking vehicle traffic to the top of the dame. My grandson and I walked the dam and didn't find any sign of any kind of shooting range. I did find a lot of "No Target Shooting" signs all around.
He was sure discouraged.
We got back into the car to go home and on a lark I decided to follow the road farther into the WMA to see what was there. That's where I saw the entrance to the one lane shooting range.
In the first image the location of the entrance to the shooting range is marked by the white arrowhead.
The second image shows the entrance gate.
The third image shows the shooting bench.
Unfortunately, the shooting range precludes the use of air guns unless they are high pressure. I'm guessing the hold-over for a .177 cal break barrel would cause a ricochet off of the top of the tunnel. My grandson and I will have to look elsewhere. Perhaps someone who lives in the country nearby.
The tunnel is of an excellent safety design which allows only one shooter at a time. A steel baffle slides in front of the tunnel entrance, where the shooting bench is, and another baffle slides over the tunnel exit. Between the tunnel exit and the targets is a small "building" made of 6"X6" railway ties with small 2' square windows on the south and north ends to allow the bullet to pass through. Bullet holes near the top edge were not more than an inch in. There are two target holders at the north end of the range. After one finishes a round of test shots they'd slide the front baffle over the tunnel entrance. Walking around the side of the concrete tunnel to its other end they'd then slide the second baffle over the tunnel exit, which would prevent someone from shooting through the tunnel by sliding open the entrance baffle. After checking and replacing the targets the shooter would walk back to the exit baffle and slide it open, walk around the tunnel to the shooting bench and slide open the entrance baffle, and resume her position on the shooting bench.
A sign on the railway tie structure between the tunnel exit and the targets forbids attaching targets over the south window on that structure, otherwise it would make a good air gun or hand gun target range.