This only teaches you how to make certain types of weapons using a modelling program you happen to like.
I'd say that bow-type weapons should be on there, too: Ranged weapons where you hold down the trigger.
Your script also overwrites the bulletHitSound, bulletTrailParticle and bulletTrailEmitter datablocks, if people change these at all they will affect the Gun as well. (and any other Add-Ons made with the Example Gun script)