The American Rifle Company, known for their rifle action called Mausingfield, is developing an interesting system of locking the threads of the barreled action. It is also rather simple consisting of a split collar and a nut.

Images by American Rifle Company

The circumference of the split collar inner edge is angled inward and one side of the nut has a corresponding conical geometry to fit the collar. The installation will require to screw the nut onto the barrel, then install the split collar with its hex screw loosened. Once the barrel is screwed into the receiver, the lock nut should be tightened against the split collar which becomes sandwiched between the lock nut and recoil lug. At that point, you should see the split collar trying to slightly open up. Then, tightening the Allen head screw of the split collar should effectively lock all the parts forcing the barrel and receiver in opposite directions and eliminating any possible movement of the two parts.

The main advantage of this system is to lock the barrel and receiver to each other as securely as possible. However, I think a side-advantage could be the possibility to change the barrel without removing the receiver or the scope. A similar quick-change barrel system exists and is made by West Texas Ordnance (see the video below):