Originally Posted by
ultimate_monkey
it depends on the platform of the rifle...
somthing like the S&W M&P15-22 is restricted at any barrel length as its an AR variant..
BUT
if you take say a ruger sr22 and BUY a premanufactred barrel at less then 18.5 install it and the gun still meets the minimum O.A.L then its still classed as non-restricted.
the same goes for shotguns, you can buty 12-14-16" barrels for like the remingtong 870 series as well as others, and its still non-res.
cutting your existing barrel down on the other hand is a BIG no no