been in the gun shop today seen one they look great but are they any good! there seem two types one with internal 12g powerlet and one with an external large co2 source so does this larger one give more power or just more shots? I have plenty of 12g powerlets which i use in my other pistols but they dont seem that powerful,yet the box said it was capable of killing rats(hence the name i suppose) is it or is it only really a plinking gun! any advice appreciated thanks guys.I must admit i prefer the look of the one without the external capsule.I want it for ratting and the occasional plink in the garden.