Originally Posted by ken snyder
It is illegal to use an action that was registered as a pistol to build a rifle and it is also illegal to do it the other way around!
Absolutely NOT true.
You can use a handgun action to make a rifle........if you want to use a rifle action to make a handgun, you must first submit a Form 1 to the batf and pay a $200 tax......after the form 1 is approved, you may build the firearm......the resulting firearm is classified as a "short barreled rifle".
To answer the original question, the federal minimum length for a rifle barrel is 16", there is no federal maximum length for a handgun barrel, some state laws do restrict the maximum length of a handgun barrel.
Minimum overall length for a rifle is 26"