38 special

I bought a colt police positive the other day, and i need a holster for it. It is a beater gun so I do not need a fancy holster. It is in about 60o/o condition but shoots great for $325

I'm considering buying a Rossi R92 in .357 Magnum? Should I go with the 16" or 20" barrel? This will probably be an under 100 yard rifle for me...