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 standaed ball is retained by the end being punched to displace the metal inwards to keep the ball from coming out. 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.
I can fit if required as the gun will need a small hole drilled near the front latch and tapped m3. £10.00.