First, remove the small setscrew holding the barrel weight in place. (First photo).

Now, you can pull the barrel weight back off of the AR2078 barrel - don't scratch the finish! Our second photo shows the removed weight and setscrew.

Now remove the screw and slotted disks. This is obvious and it looks as if the front sight should now slide off. But it doesn't! The secret is that there's actually a spring steel roll pin holding the sight assembly tight to the barrel. You can see it if you look carefully at the next photo.



Having removed the front sight, you are left with a flat in the underside of the AR 2078 barrel for the setscrew seating and an unpleasant semi-circular slot in the top for the roll pin. A muzzle brake will cover these if it is long enough. In practice, I find that the barrel weight removed in stage one can be epoxied back in place around the front of the barrel - this makes a nice, clean job and this is how I finish our AR2078A "Custom" air rifles.