I just re-chambered my own 22 hornet. Rented a reamer and turned it into a k hornet. Reamer showed up in 2 days, barrel was all stripped down and locked up in a vise. Turned the reamer by hand with a tap wrench, used with lots of cutting fluid. 20 minutes later, I had a K hornet. Cleaned and oiled the reamer, put it into the prepaid shipping box and mailed it home. Now I just need to find time to go and convert a bunch of hornets. I ordered from Reamer Rentals, but there is another rental service that is a site sponsor here also. Both work pretty much the same. If you are just improving an existing chamber, say to a K Hornet or like a 30-30 Ackley improved, it is a fairly simple process that you can do yourself. Especially when dealing with a contender barrel and rimmed cartridges. Just run the reamer in until the original rim recess is just touched by the reamer and you are done.