Restricting weapons in AMX is fairly easy and can be done two different ways. The first method is with the Restrict Weapons menu. Below is what the first page looks like. You activate this menu from the amxmodmenu, or by using the amx_restmenu command in your console.
Each weapon can be toggled ON (restricted) or OFF (not restricted) by selecting the number in front of what you want to restrict. Option 9 will show you additional weapons not shown in the first page of the menu. The weapon(s) will remain restricted for the rest of the map and become available again on the next map. If you want the weapons to be permanently restricted, choose option 8 to save the restriction(s) you made. Likewise for unrestricting, if you have saved weapon restriction(s) in place, and unrestrict a weapon you need to save your settings or the weapons will be restricted again on the next map.
The second method for restricting weapons is via the server console or using rcon. Type the command amx_restrict in your console. You will get this:
Basically, your commands are:
The weapon categories are listed as ammo, equip, pistol, etc. By restricting a category, all items in the category are restricted. So by restricting pistol, no one can purchase pistols.
To restrict a specific weapon, do amx_restrict list in the console to see a list of weapon names. The value column contains the name you use to restrict with. Here is what amx_restrict list shows us:
amx_restrict list 11 will show you additional weapons not shown on the first page of the list. Use the same method for the third (21) and forth (31) page also.
If you wanted to restrict the Desert Eagle, you would do it like this:
And then amx_restrict list would show you this:
To unrestrict it, just use off instead of on. The command amx_restrict save will save your changes and make them stay that way until you change it again.
These changes are kept in a file called weaponrest.ini in the addons\amx\config folder. This is a text file and can be opened as such, but it's recommended to use one of the two methods above for making changes to weapon restrictions. If this file is edited while the server is running, unpredictable results will probably occur. This file doesn't exist until changes are saved using amx_restmenu or amx_restrict.