If you have your own ruger 10/22 mag.........just order a bull barrel in the 17 cal. (There may be a shim kit that needs to be ordered also) remove the barrel from the mag., and add the bull in the 17. cal. You then have your own 10/17. Nothing else to change except the barrel. Everything works great. Oh ya, forgot, you will need a new stock for the bull, unless your open up the original mag stock............
Green Mountaion 77/17 barrels, but others will work.
You remove the 10/22 mag barrel and replace it with the 77/17 barrel. You place a spacer (washer of special width) over the barrel shank before mounting the barrel. Then you give the barrel about a 30-degree "cant" to line up the extractor groove with the extractor (which are in different places on the 10/22 and 77/22)
There is an angled shim supplied to help out with this.
Then you grind an angled area out of the v-block with a dremel or similar instrument and screw it down.
(Lilja or Clark 10/22 Magnum 10/17HMR drop-in barrel or get the GM or Volquartsen 77/17HMR barrel and the shim kit.)