[speedevil]

This is the flat spring that fits into the barrel band and bears on the magazine tube to hold the forend in the forward position. The online places I've checked (Numrich, MGW, Jack First) say "discontinued" or "unavailable".

 

[wahtsamoie]

I have several. Both new and used. PM me I can fix you up with one or more.

 

[g7777777]

I have