diff --git a/code/game/objects/items/pneumaticCannon.dm b/code/game/objects/items/pneumaticCannon.dm
index 3aba3d05f2..b3960d1e5f 100644
--- a/code/game/objects/items/pneumaticCannon.dm
+++ b/code/game/objects/items/pneumaticCannon.dm
@@ -98,7 +98,7 @@
 		load_item(IW, user)
 
 /obj/item/pneumatic_cannon/proc/can_load_item(obj/item/I, mob/user)
-	if(allowed_typecache && is_type_in_typecache(I, allowed_typecache))
+	if(allowed_typecache && !is_type_in_typecache(I, allowed_typecache))
 		if(user)
 			to_chat(user, "<span class='warning'>[I] won't fit into [src]!</span>")
 		return