Modification of the Lyman 55 powder measure.
The old style 55's had a spring steel clip that held the funnel / drop tube.
On this one, there was a small amount of loose fit.
Each time I would fit a case in the end of the drop tube and drop a charge , I could feel " a bit of wiggle ". I didn't like that............
I decided to remove the clip and drill and tap a 10-24 threaded hole and install a set screw. No loose fit now. Solid as a rock.
Seems from reading about the old Lyman 55's that I'm not the only one to do this modification. Very common.
At some point in the past, Lyman abandoned the idea of the spring steel clip / spring to hold the drop tube instead going to a threaded screw.
Ben