three magazines
They must not plan on getting into a shooting match with the Tallies. The MP5N as used by the SEALs fires 800 rounds per minute. If the team is carrying the typical 30-round stick mags (or even the newer and rare 40-round stick mags) that is not a lot of ammo for a SMG. Some of the guys with the MP5s would also be carrying an M4.
