I needed a 75 more than a tuna gun... so I made one.
The mechanism is made to fit directly into the stock. I used a 3/16 thick 316 stainless flatbar for the mech. The line release is located on the bottom. The stock is only 31 mm high and 34 mm wide. It's set for a single band and a 6 mm shaft. If it floats too much I'll put a 6.5 mm and 20 mm bands.
I used polyurethane to inbed the handle.

Mechanism.

The band aligns with the shaft.

Real line release system.


The handle was made for a right handed person.
The center piece is mahogany and the sides are walnut.

Thumb rest on the left.

I will probably cut the butt.
Here it is shooting :
Again (watch the shooting line!):
The gun was too light and I found the square butt unbecoming.

The trigger was a bit hard and I have since changed the whole thing, lengthening the nut and all. I think this gun helped me find a definitive mech design for here on end. It's smoother than the Marc Valentine from what I can see.
The 75 cm speargun saga continues...
www.renepotvin.com