I think that Jim missed the previous posters point.....
FWIW; I just checked the twist on my Marlin/Glenfield .30/30 and it's a 1/12" twist M/G barrel.
The problem with the .30/30 from a l/a will be more action length and case capacity. Most cast bullets suitable for the .30/30 are 200gr or lighter. The longer cast bullets will contact the lead in the barrel (rifling/throat), limiting how far out they can be seated and with the depth of seating, will limit powder capacity.
Additionally, I've found that with the cast bullets, having the base and lower driving bands exposed to the powder combustion seriously deteriorates the accuracy, hence the wonderful long neck of the .30/30 making it highly suited to cast bullets.
I've found that for best velocities/accuracy, that the .30/30 just about peaks out with a 170-180gr bullet. My personal favorite for over 3 decades is the Lee 150gr FNGC which casts to 158-162gr depending on alloy and mould..... A second favorite is the 170gr Lee FNGC which casts to 180gr and with bullet crimped to the crimp-grooove puts the gascheck right at the base of the neck preserving the integrity of the groove and lube and driving band just above it.....
And yes, the 180gr FN does about anything you'd want from a .30/30.... From low velocity "QUIET" plinking to heavy deep penetrator.... A heavier bullet than 200gr will likely "key-hole" drammatically reducing penetration....
Jacketed bullets of up to 240gr "CAN" be shot, but won't likely be offering any benifit....