AR-15 Windham Weaponry Government 20" and the Sightron STAC 10Oct2021

Sighting in the Windham Government 20" iron sights today at the standard military 25 meters and got very close to where I wanted to be with a 50 yard zero using the Sightron STAC before I ran out of ammunition. I was using some 55 grain 223 factory reloaded with different head stamps and new Winchester 55 grain 556 NATO for the final zero. NATO definitely had more pop!