Thinking of buying an 1894P from a buddy, but have a few questions I'm hoping someone can help with. 1. What years or how many years was the P model produced? 2. Why was the P model discontinued? 3. What are the differences in the P model and the standard 1894? In other words, is the only difference the barrel? Are the receiver and stock the same? 4. Will it be hard to find parts should something go wrong? 5. What is the reason for the trigger being on a "swivel"?