Looking at a Winchester Model 50, The - it has a Polychoke which I'm not all too excited about. Could that be lopped off the barrel and the barrel be threaded to accept a modern thread in choke tube such as Browning's Invector or Invector + choke tubes which I belive is what's in the new Winchester shotguns? Thanks. Also what's a general estimation of the cost of such a trip to the gunsmith's?