Barrel for what? Single shot rifle. TC? Is it possible by hand? Yes. Is it a "good idea?" Probably not. Some 'smiths will do the chamber by hand (or in the lath with the power off) to get maximum "feel" but they know almost all there is to know about what they are doing...
#1). Many Hornet barrels were 1 in 16 twist or 1 in 14... I believe the .221 was faster twist usually. Are you willing to be restricted to the lightest of bullets? For what gun? Is is strong enough for the .221? I believe it works at almost twice the standard pressure of the hornet... 50% more for sure. 35K CUP vs 55K CUP...
#2). If you have unusually steady hands and alot of experience at machine work... Maybe. If you are a novice... the lath prevents alot of slop with kills accuracy, case life, etc. LUCK!