How does the BARLOC™ work?
It works very well.
The BarLoc is an adjustable shoulder like a barrel nut but it uses a little slicker interface to produce the preload into the tenon joint than just a glorified tube nut does.
The BarLoc has a split ring that is similar to a scope ring in design. It’s meant to collapse around a tube and grip it. The difference here is that the BarLoc interfaces with a coned washer on either side that has a mating cone on the BarLoc washer. These mating cones fit at a nominal overall thickness without any torque applied to the locking screw.
When the locking screw is tightened the split ring of the BarLoc closes down and forces the mating cones outward. When this happens the stack height of the system gets larger.
If there is nothing to resist the growth of the stack height that doesn’t do much so we need a way to resist this motion. However, if we place a receiver on one side and a shoulder of some sort on the other then we can use the growth of the stack to generate forces along the length of the barrel.
Anyone that’s ever cut the head off a bolt to relieve the tension in the bolt knows how easy it becomes to remove a stuck bolt once the head is removed completely. The BarLoc works on the same principles.
This approach allows a user to take a headspace gage (GO Gauge) and a 5/32” wrench to change barrels in the field. Since the BarLoc screw can be tightened by hand and in turn generate 100+ ft-lb of torque in the tenon joint there is a viable way to change barrels in the field without permanent design modifications to the receiver.