Within Multnomah county and the towns that have restricted UNLICENSED LOADED CARRY, yes, you cannot carry loaded without a license to carry a concealed weapon. ORS 166.173. You can carry unloaded. Portland wants you to think your magazine cannot be loaded but that is not what the law says, The weapon cannot be loaded, but nothing in .173 authorizes any restriction on a loaded magazine. However, this little nuance has never gone to court so Portland still tries to enforce this provision, Just do not allow them to search your person, it is a very well established principle that the openly carriage of a firearm, where legal to do so, is not RAS under Terry to search a person. (Black and Delaware V Prouse)
Outside of those local government areas (Gresham is NOT on) that restrict unlicensed loaded carry, you may carry as per ORS 166.250(3). 1: Make sure it is in a holster on your hip and visible. 2: in unrestricted areas it may be loaded 3: in restricted areas it may not be loaded. Remember, the exemption is specifically for #1
Multnomah Co., Portland, Beverton, Tiagard, Independence, Oregon City, Salem, and Astoria. Also Parks (only) are restricted in Springfield and Bend. I know there is another town down on the coast, but I forgot which one (either Lincoln City or Newport). To my knowledge this is it. Check with OFF, or the sticky at the top of this Oregon forum.