IMO examine the bore by looking down it is a perfectly safe way of examining the bore when done safely and common sense is used. Follow the steps point safe, remove cartridges, observe chamber, verify feeding path, and with the action open and safety on (if available) examine the bore. Simple, safe. If you observe a cartridge in the chamber, stop and do not examine the bore! (duh) tap out the cartridge with a cleaning rod, observe the chamber again, verify the feeding path again, then examine the bore. No big deal. If there is nothing sitting in the chamber, and the action is open, and the safety is on (optional) it is impossible for anything bad to happen. If you don't feel comfortable examining the bore from the business end, then just always use a cleaning rod.