CYMA trishot doesn't always cock

[Lollingsgrad]

Got a CYMA trishot and played with it all day Sunday. It was surprisingly good although seemed to degrade very quickly. Towards the end of the day, about once per shell I'd cock it and it'd feel a bit harder than usual. BBs will load into the barrels but the spring won't have locked back. Without fail when I cock it again it will load the spring correctly but then the next shot will be a mess of 4-6 BBs that obviously don't go very far.

My understanding is that when these things start to malfunction it's pretty much bin-time because there are no replacement parts and disassembly is a nightmare. That said I'm not quite ready to give up on it because it's fun and it does shoot well most of the time. Can anyone experienced with the inner workings of these things give me an idea of what could be wrong and what it'd take to fix it?

 

[EDcase]

Yeah unfortunately the internals are mainly plastic so its doesn't take many cycles to wear down a sear or other component to stop it functioning properly 

If it starts failing badly you may as well open it up and tinker with it.  There might be a chance you can cobble something to fix it...

 

[Rogerborg]

The feed mechanisms are fragile as frag.  Mine didn't even last to chrono on the first game day, and just shoves as many BBs as it can fit into all three barrels.  The only decent YouTube disassembly video I can find mentions (and was prompted by) this issue.

Also, they do take ages to strip down, longer than an AEG, with loads of tiny screws put straight into plastic.

Sorry, I know that's not what you wanted to hear.  <dem-feels.png>

 

[Lollingsgrad]

Sorry, I know that's not what you wanted to hear.  <dem-feels.png>

It's a different problem at least, most shots are fine and it only overfeeds when this problem with the spring not locking back occurs and I have to essentially double cock it. It never happens when dry firing; a major clue seems to be that when this occurs the pistons haven't managed to lock forwards. I wonder if getting some lube onto the pistons and into the feed tube, getting some BBs through then cleaning out the barrels afterwards might help, what do you think?

 

[Rogerborg]

Couldn't hurt to spooge it with lube.

I mean, it could hurt the hop rubbers, but getting the slide mechanism slicker would be an idea.  I'd also get some silicone up beyond the trigger if you can, there's a lot of levers and catches in there.

Technique-wise, it's easier to positively cock it in one action if you push the whole gun forwards with your trigger hand rather than pulling the slide back.  I know it's the same amount of energy going in either way, but it seems easier push a bent arm forwards than to pull a straight one back.