Complex sentence: Members of ATF are issued the Glock 22 or the Glock 27 as their sidearm while the agents are trained in the use of, and issued, long arms if it meets certain requirements.
Split into simpler sentences: Members of ATF are issued the Glock 22 or the Glock 27 as their sidearm. While the agents are trained in the use of, and issued, long arms if it meets certain requirements.