Help with trigger release

[onefish]

G'day all,

I've finally found time to get back out on the water a bit and my gun is stuffing up (arggg!). It worked fine for the first few shots but then the catch on the piston when cocked would hold until I started to release pressure from the spear then it let go. Nearly ripped my are off, me being a bit slow to learn tried again (there was a nice trout looking at me). Same thing, big bruise around my wrist from the lanyard, gun boated!

I thought it was the piston supplied with the Tovarich so I swapped the piston back to the original yesterday morning at 4:30am and headed out for the day. Same problem!

Just wondering if there may be something obvious before I pull the whole gun apart. I did install a trigger kit, any ideas?

Cheers,
TJ

 

[popgun pete]

Pneumatic spearguns of the "Sten" type (which most on the market today are) use a sear lever which is virtually a single-piece trigger flattened out like a playground "see-saw". They hold the piston's tail by virtue of the sear's 90 degree sear tooth profile hanging onto the matching 90 degree surface profile of the mushroom head tail on the piston. If these vertical surfaces develop an angle then the force pulling on them no longer passes directly through the sear pivot pin and the sear will tend to roll open, thus releasing the piston without you having to pull the trigger. The external trigger that you actually pull with your finger drives a short connecting pin that passes up through an "O" ring seal and presses on the rear end of the "see-saw" sear lever thereby tipping it over and firing the gun.

If the piston is not holding then it has developed an angled face or something is stopping it coming up and engaging the piston tail properly in the first place. A biasing coil spring pushing down on the far end of the sear lever is what pushes the sear tooth up to engage the piston, that spring may have fallen out. This coil spring is directly above where the short connecting pin pushes up from below on the sear lever. You need to check this spring for correct positioning, it can tip over during assembly, so the gun has to come apart again, otherwise you have a very dangerous situation where you have no way of knowing if the sear will hold.

 

[onefish]

Thank Pete,

I know the spring, it was a pain to get it back together without it sliding out, took a couple tries. I was hoping it might have been something simple like I screwed the housing for the pin in too much. But I suppose I'll pull it all apart again and find the problem. The lever/sear/pivot thing shouldn't have developed an angle, the gun's not that old. I guess I'll find out.

Cheers,
TJ

 

[Mongrel454]

Have you adjusted the trigger 2 far so its a light touch?

If so try adjusting it back to factory.