Same happened to me - after the restart (12am) i logged in and had no gun.
I also noticed that i had money on my person which i had previously depositied. Is it possible that the server does not sync properly before a restart and we end up having a 20-30min rollback after each restart?
I bought the gun and depositied the money between 11.30 and the restart, syncing my data many times in the process.
Well I lost my clothes my rifle which I have had for days my backpack & everything in it.
On the bright side when I spawned this morning I had my boonie hat, combat goggles & handgun minus ammo.
So I have just spent half an hour running around in the dark in my underwear with no map, NVG or any other equipment trying to locate shops to gear up.