I would recomend either Mike Orlen or Simmons Gun Specialties in Kansas. Bother have web sites and are expert at what they do. Mike may b a bit cheaper but you must be certain to specify the type tubes you have and are wanting to use. It may be best to send it along with the barrel... It is likely that you can buy a barrel for your Mossberg cheaper than installing tubes in your existing barrel. You may want to check out the for sale part of this site and perhaps GunBroker/AuctionArms to see what they are bringing..
