HW 77 Front Latch Mod, Made in Stainless Steel for the type that has a sprung steel ball. These often pop out after a little wear.
The standard ball is retained by the end being punched to displace the metal inwards to keep the ball from coming out. But after some use these will often come out so it will not hold the under lever up anymore.
My conversion will last a very long time, probably before the rest of the gun gets worn out.

The hole should be drilled with an M3 tapping drill (around 2.5mm) so that the latch is held where the ball would have been, this is so it will rest on the rear outward groove of the new latch.

I can fit if required as the gun will need a small hole drilled near the front latch and tapped m3. £10.00.