Fixed issues related to shotguns and their shells.

-The description "A weak beanbag shell. This one is spent. This one is spent. This one is spent. This one is spent." made by double barreled shotguns is gone, now the message is only added when the shotgun actually fires and uses the shell
-All other kind of shotguns will now add the "This one is spent." message.
-Shotguns will stop firing invisible bullets, making them less confusing.

Changed the "You break the double barreled shotgun" message to "You open the double barreled shotgun" because it was confusing, the playes (myself included) thought that they actually ruined the pretty gun.

code/modules/projectiles/guns/projectile/shotgun.dm

@@ -18,6 +18,9 @@
 
 	load_into_chamber()
 		if(in_chamber)
+			var/obj/item/ammo_casing/AC = current_shell
+			AC.desc += " This one is spent."
+			AC.BB = null //remove the ammunition from the shell
 			return 1
 		return 0
 
@@ -86,11 +89,12 @@
 
 		var/obj/item/ammo_casing/AC = loaded[1] //load next casing.
 		loaded -= AC //Remove casing from loaded list.
-		AC.desc += " This one is spent."
 
 		if(AC.BB)
 			in_chamber = AC.BB //Load projectile into chamber.
 			AC.BB.loc = src //Set projectile loc to gun.
+			AC.BB = null //Remove the ammunition from the shell
+			AC.desc += " This one is spent."
 			return 1
 		return 0
 
@@ -104,7 +108,7 @@
 				loaded -= shell
 			shell.loc = get_turf(src.loc)
 
-		user << "<span class='notice'>You break \the [src].</span>"
+		user << "<span class='notice'>You open \the [src].</span>"
 		update_icon()
 
 	attackby(var/obj/item/A as obj, mob/user as mob)