For me it depends on the gun and it's type of action. For example if it's a bolt action rifle, all I'll do is run an oily patch through the bore and grease up the bolt lugs. If it's a semi auto pistol like a 1911, or the new CZ-75B I just bought, I will do a complete field strip, clean and relubricate everything, especially the slide. On an AR-15 I'll ALWAYS pull out the bolt carrier group, disassemble, and completely lubricate everything. I've yet to see a new AR-15 that wasn't shipped from the factory bone dry. I would never fire an AR-15 in that condition.