As a member of a formal military marksmanship team, I had U.S. Army weapons issued to me for about two decades for training and competitions. I stored these weapons locally (not in a military arms room) and even in my home as directed by AR 190–11.
AR 190–11 (Physical Security of Arms, Ammunition, and Explosives) directs how Soldiers can check out unit weapons like this:
Chapter 4 Protection of Arms
4–6. Weapons and ammunition for marksmanship matches and other special purposes
a. Weapons and ammunition for marksmanship matches and other purposes will be protected at all times.
b. When not in use, marksmanship weapons used in matches or ceremonies away from a military installation will be stored in authorized Regular Army, ARNG, USAR, or ROTC arms rooms. Weapons and ammunition may be stored in a civilian police station under police control. If these facilities are not available, weapons and ammunition will be stored in locked containers or rooms attended at all times by at least one team member or designated person.
d. Exceptions to paragraph b, above, for marksmanship weapons are authorized for ARNG, USAR, and ROTC marksmanship personnel when firing as persons away from their teams. Exception criteria are as follows:
(1) Eligibility is limited to persons who are active members representing an ARNG, ROTC region, a major USAR command, or higher-level team. Eligibility is limited only for a specified period of marksmanship participation. Weapons will be returned to the proper authorized arms rooms for storage upon completing the marksmanship match.
(2) Exceptions will be held to a minimum. Each written request for exception will include a statement that other secure facilities are not available. Each request will outline compensatory measures to be applied. If weapons are to be stored in private homes, the weapons will be secured in a locked, metal container. The container will not be prominently displayed. It will be secured to a firm structure in the home.
(3) Arms used during matches or practices away from the facility and not secured will be stored under paragraph b, above.
TL;DR, Commanders of any unit with an arms room are authorized to allow any of their Soldiers to take unit-issue weapons out for marksmanship competitions, events, and training, even to civilian ranges and transported in civilian vehicles. If not stored in a military arms room or similar, they can be secured by having at least one designated Soldier guard them by staying in the vehicle or room with the weapons at all times until stored in a military arms room.
Personnel formally assigned to a marksmanship team in ROTC, state-level National Guard or higher, or Army Reserve MACOM (Major Command) or higher may have military-owned weapons issued directly to them. These can be secured locally (police station or similar) or at home, if properly secured as detailed above and confirmed by written permission with the shooting Team OIC/commander. A hand receipt will be signed and submitted by the Soldier and returned to the Team OIC every month to confirm that the issued weapons are still secured.
Most Army personnel remain unaware of what Regulations actually say. Most are not involved in high-level marksmanship events. Commanders will be blamed for any misdeed by their subordinates even if it was not the commander’s fault and will usually default to the most restrictive approach (“Keep them all locked up all the time!”).
If your unit does not have a marksmanship team, that is your fault. Watch the videos above to get started. Knowing what the regulation actually says will help convince your commander to get a program started.