get a set of go/no go guages from midway, the safest most easiest way to set head space. when changing the barrel screw the barrel in on the go guage until snug by hand, then back it off about 1/16" turn, then tighten the barrel nut. then take out the go guage and put in the no go guage. the bolt should not close on the no go guage if you have it set right, if it does loosen the nut and adjust the barrel. you can place a witness mark on the barrel to speed things up next time. the barrel may or may not already have witness marks on it from the factory. i doubt it since they dont like the switch barrel crowd.
you will need a barrel nut wrench(for the correct type nut), action wrench and a vise to do it. when you get used to switching barrels you'll be able to do it in ten minutes.