What mod are you using, if any? Because to my understanding, if weapon physics are turned on as they are in Airmod, the weapons in the chest will fly everywhere at the start of the map and will not appear in the chest. Aside from that factor, following the setup instructions from the original post will get the chest working properly.
Quote: "SETUP
1. Set the chest entity to dynamic, and set its main script to randomweaponschest.fpi. Set it's 'is immobile' setting to 'yes'.
2. Position the guns/items you want to be in the chest to your liking. Set each weapon with a corresponding script; 'weapon.fpi', 'weapon2.fpi', 'weapon3.fpi', and so on. Make sure all the guns are set to 'always active' and choose 'yes'.
3. Put the included HUDS into the appropiate directories, and make sure the weapons scripts' file paths are correct to display the HUDS.
4. That's it! The scripts take care of the rest. When you walk up to the chest, press enter and the script will throw out a random weapon from the weapons you put in it. You can either press enter to pick that weapon up, or back away from the chest to throw it back in, and pick again!"
Kravenwolf