Rifle practice in basic training.

I can't tell from the film how far he was shooting, but at that time American riflemen were trained to hit targets out to 600 yards. You can verify this yourself on Google Earth. Find rifle ranges on military bases which existed at that time and use the measuring tool to see for yourself that there was a target line at 600 yards.

It looked to me to be his first day of range training. And, he was training to be an infantryman, not a sniper. So, it's not likely that it was more than 100 yards - more likely 50 or so.

I don't know about WWII but we shot out to 300m with pop up targets. We did have ranges just like the one where York shot and sometimes used them for sighting in or competitions.