How often should I clean my gun? Do I need to clean it after every time I shoot it?” The answer to that question is, “It depends.”
If you are cleaning a range toy rather than a defensive gun, you can probably allow the crud to build up a little bit before cleaning it, even though it is usually somewhat easier to remove the crud when the cleaning is done immediately.
Modern powder is not corrosive, and so it won’t eat its way through the metal of your barrel if it gets left in there for awhile.
The fouling can and often does affect reliability, however. Uncleaned guns are more apt to jam when you most need them. Because the crud can slow down the slide, dirty semi-automatic firearms are prone to failures to feed or failures to completely eject the spent cases. Uncleaned revolvers are prone to binding up, and the double-action trigger can become difficult or impossible to pull if the cylinder isn’t turning easily. Poorly-cleaned or uncleaned firearms are thus far less reliable than their well-cleaned and properly lubricated counterparts.
For this reason, we highly recommend that you clean your defensive handgun immediately after every trip to the range, no matter how many or how few shots you fire. Since you will be betting your life on the function of your gun, it’s a good idea to keep it as clean as you can, in order to avoid fouling-related problems.