found problem:
if($Pref::Server::WHAmmo == 0 || $Pref::Server::WHAmmo == 1)
{
%obj.toolAmmo[%obj.currTool]--;
%obj.AmmoSpent[%obj.currTool]++;
commandToClient(%obj.client,'bottomPrint',"<just:right><font:impact:24><color:fff000>.75 Cal Bolt <font:impact:34>\c6" @ %obj.toolAmmo[%obj.currTool] @ " / " @ %obj.client.quantity[".75 Cal Bolt"] @ "", 4, 2, 3, 4);
}
in server.cs you are setting it wrong.
RTB_registerPref("Starting Lasgun Ammo","WH40k Ammo","$Pref::Server::WHAmmo","int 0 100","Script_GamePreferences",50*2,0,1);