Usually, the problem is finding ammunition. Not like you're normally going to have a massive selection to pick and choose from. That said, WWB FMJ is average. The easiest way to keep the 686p clean is to keep it clean. That means you give it a thorough cleaning after each use, regardless of the number of rounds fired and don't put the gun up until it's cleaned and lightly oiled. After each 250-500 rounds, remove the crane and cylinder and perform a more detailed cleaning.
Your goal should be to practice with the gun as often as possible, and if you can, find ammo that helps the gun shoot to POA.