The minimum legal barrel length for a rifle without requiring it to be tax stamped and registered as a Short Barreled Rifle is 16 inches - that's federal law, and not just Vermont.
In Ohio, the legal minimum barrel length for a rifle is 16 inches. Any rifle with a barrel length shorter than that would be considered a short-barreled rifle, which is regulated under the National Firearms Act (NFA).
Any barrel length and overall length is legal in the US. However, rifles with barrels less than 16 inches and overall length less than 26 inches are regulated under the National Firearms Act, which means that buying one or making one you have to pay a special tax. There are forms to be filed with the ATF and you get a special stamp as proof of payment.
16"
16 inches
No
As long as you follow all Federal laws, any length you want.
Barrel length is usually 20 to 26in, but can be custom depending the environment.
To legally own a long gun (rifle or shotgun) in Tennessee, you must be 18. To legally own a handgun in Tennessee, you must be 21.
colt
H&R and I believe Rossi have single shot rifles with interchangible barrels.
Heavy Barrel