A simple cable lock will work just to keep unauthorized little fingers from firing it. I read this post and took this bad cell phone picture to show you what I mean - the blue cable lock came with one of my CZ pistols. It will work just fine.
As a THEFT deterrent, not even - a person with EMT shears can probably go through that thing. Hiding is one option, a cheap gun locker is another. They aren't much good against someone determined with time and a hammer, but they might last long enough for your average tweaker to give up to steal the TV instead. Get a bio hazard warning sig for the front, "Warning - Fossilized Fecal Matter" or something, to throw them off.
A real safe is the best form of theft deterrent, but REAL safes cost THOUSANDS, not like the high speed residential security containers everyone sells as safes. A good RSC from a reputable company like Fort Knox, bolted down, is a great peace of mind.
