In the manual that came with my Bushmaster AR-15 its states something along the lines of not cleaning the rifle until several hundred rounds are fired through it- something about polishing the oxidation off the chrome lining.

I've been called a heretic and even a lazy slob, but I don't clean rifles very often. I'll run a patch with some hoppes or CLP down the bore then put it away. .22 rimfire bores never get cleaned unless on the off chance they get wet somehow- its only happened to me once while shooting NRA rimfire sihouette in the rain.The M1 garand I used for several seasons of high power rifle only got cleaned at the end of the season- there's no point in cleaning it as the first 2-3 shots will be off after a cleaning- they might not be off by much but the first one will become a complete throwaway round instead of a sighter, the second would be a sighter that would be off- not doing me much good, and the 3rd and/or 4th shot would score a 9 instead of a 10- and that's only if I ignored the the deviation in my sighters and trusted my zero.