i would think for best results you would want to send the action in so the head space and everything can be double checked before you start running live ammo through it. it would suck for you to have a smith spin up a barrel for you to what the action specs are SUPPOSED to be and have something be slightly off on the action so the barrel wouldn't work properly. you could have a few barrel spun up at once for your action so you could switch back and forth at home, i think that's more the point of the integral recoil lug. that being said, if everything was always perfect on the actions there shouldn't really be any reason you couldn't just order a barrel for the specific action and screw it on yourself.