Here's a thought...since so many cops want to play soldier, treat a missing weapon just as the Army would. As soon as a weapon or other sensitive item is identified as missing, initiate simultaneous, full blown administrative inquiries and a criminal investigation. Lock down the department and nobody goes home until every wall locker, private auto, etc. has been thoroughly searched. If the weapon is not located or otherwise accounted for, relieve the responsible parties starting with the armorer and start working up the chain of command. Where criminal negligence is identified, prosecute.
At the bare minimum, somebody's paycheck is a little short 'til the weapon is paid for.
Cops want to play soldier? What's sauce for the goose is sauce for the gander...