I wonder if many shooters used this feature as it would seem very fragle if bumped.
The EFS was designed and intended for a specific type of target shooting,,
it would not be something that you would carry around and plink with.
I had a 41 with the EFS, it was hard to move so I used a small block of wood and gentle hammer taps to get it going. I think some oil was under it and had gummed it up a bit. The EFS was quite sturdy and not as fragile as mentioned.
My EFS Model 41 sight would not move, the Allen screws were locked.
I put Kroil on the screws, and put the gun away for 2 years,,
yes,,, literally two years,,,
The next time I tried it, the screws turned like they were not previously tightened,,
the sight slides easily in the groove of the barrel.