M4 Mastery A special warfare airman fires an M4 carbine during a live-fire exercise near Gowen Field in Boise, Idaho, Oct. 17, 2019. SHARE: Download: Full Size (2.59 MB) Tags: national guard, air force Credit: Air National Guard Senior Master Sgt. Joshua C. Allmaras VIRIN: 191017-Z-IM874-0337Y.JPG Photo Gallery