Marlin put a 24" octagon .30-30 barrel on a 336 for me, the "cowboy conversion". Beautiful wood for the forearm, they put a foreend cap with sling swivel stud on since I had put a forearm band with stud on the original barrel. They sent me back all the old parts with the rifle. Total charge was $320 IIRC.
Then I sold it (kick myself in the butt over and over again).
-WH-