Private, gun collector / trader
Private collectors are a mixed bag when it comes to obtaining guns. Usually they are difficult to find and it is an art form to be able to know enough to ensure that you have much of a selection to shop from. In general, these folks do not necessarily trade at a profit, so the numbers work pretty well with them. This meaning that everybody trades off the same set of books, not one guy dealing wholesale and one at retail. Private collectors almost always will work a better and more fair deal on accessories, whether you are buying or selling, they have a better appreciation for the value of custom work, but know that used prices will be lower than new prices. Be firm on the issue that an item must function in order to have value. A broken scope or bipod does not ad any serious value to a deal. Nor does a defective magazine or torn canvas case. Private collectors may have more personality quirks to deal with and this can sometimes reduce the value of a deal even though the numbers look good. Private collectors usually prefer to keep their transactions private, but since they usually accumulate guns, they can be found out by hostile authorities and or thieves who can then find out about you.