yep, it's very easy to do on those. Unscrew the end ring, and underneath you will find the lens carrier, turn that out perhaps 1/2 a turn (best to do it on a range so you can do it to a desired range), screw the ring back up... job done.
Mine was so easy to do i could do it with my hands, no tools required. I had to be careful to make sure the end ring was tight, because it came loose on my springer, but once sorted properly it stayed where it was.
BFTA/NSRA County Coach
CSFTA Chairman/BFTA Rep