I shoot the 30/30 in a couple of variations.
my 14" barrel is great with about everything i used in it. Even does pretty fair with factory loads for that matter. Handloads with the Hornady Single Shot Pistol bullets run about 1.5" with a couple of powders. have never gotten it to break the 1" barrier yet, but i'm still trying...
My 14" 30/30 Ackley Improved is perhaps a bit more of a good thing...better accuracy, better performance, etc. Plus you can still shoot factory loads if you want to.
I used to have a 10", but found it lacking compared to the .30 Herrett in a 10" tube. Accuracy was not so great, & fireball/blast was pretty bad... like Jim S. said, i also think your better off with a herrett in a 10 incher.