Hi,
I have a Mossberg 42M that my grandfather bought in 1942 and am getting ready to give this to my nephew, cleaning it up and gathering literature and the writing up the history for him. We have all the accessories for it including the original Mossberg front sight that has a set of different posts that swing up into place by depressing a spring at the front. This part is causing me some real issues. I'm not sure how to post pictures on this site but if anyone is familiar with this sight, it is listed as 'S101' part number in an ancient Numrich catalog, but does not show it apart. The issue is the leaf spring is supposed to be trapped by the shoulder screw that attaches the sight to the barrel keeps slipping out of place in its slot, so the front of the spring that is the lever part pops up way to high and the posts are loose. Is anyone familiar with this sight?

The same picture that is in Numrich is here, about 2/3 of the way down:

http://www.rifleman.org.uk/Mossberg_42MB.htm

Thanks,
Bob