AEG's going off randomly - Cyma cm.518 SAI

[M4freak]

about 20minutes ago, my Cyma cm.518 SAI just randomly went off, with no apparent cause, the safety was on, and it wasn't in use, is this a common problem with Cyma brand guns, a freak accident, or do i have a ghost in my house, im not too familiar with Cyma, as its the second product iv owned by Cyma, one being a glock 18 type pistol, and the one mentioned

[Samurai]

Never had this. Is it modified any way? Did it get wet?

[Sitting Duck]

Ghost

 

the Cyma & SRC's have prongs at back of switch that the copper plate on the fire selector plate MUST make contact with

In safe mode, the trigger is prevented from moving the trigger trolley forward and making contact with main contacts

BUT it will NOT fire if the prongs at the back of switch unit are not bridged by selector plate as explained

 

So in a round about way they have a double safety measure to prevent firing in safe mode

 

In fact these prongs at the back can sometimes not make proper full contact over time - more often in semi

So many in the end bridge the prongs or bypass/replace switch when they upgrade blah blah blah

 

 

Soz for long waffle but very unlikely to happen in these type of trigger switch guns

 

The gun could have pre-cocked at near full piston retraction and teeth stripped or AR latch spring broke

(but it would be a bit knackered in teeth or AR issue - dry test fire the gun)

 

if you stripped it then the tiny receiver pin could have punched through the positive wires leading up to switch

But this would have to be a bad wire arrangement to allow them to be in the way of the receiver pin to short them

(bypassing the switch completely - even with its extra prong crap)

Though this short would cause the gun to fire very often and more than just once.....

 

Could be possessed in which case you don't need a tech you need a f*cking priest

(keep an eye on it & the number of your local church handy perhaps)

 

Think this a weird - very very weird one off and as Samurai asked could of got wet

very freaky but keep eye on it coz it really shouldn't happen due to extra safety

 

One last thing- best remove battery when storing

If the battery was already removed.....

 

RUN - GET THE F*CK OUTTA THERE !!!!!!

 

[M4freak]

The gun hasn't even been used on a site yet, and of only changed the muzzle break and magazine, non of the internals have been modified 

[Sitting Duck]

10 minutes ago, M4freak said:

The gun hasn't even been used on a site yet, and of only changed the muzzle break and magazine, non of the internals have been modified 

 

Very strange - If you had this spring downgraded by TWG or somebody they might have nicked the wires with pin

but very unlikely as they can't need to go near that area to change spring

 

Could be a short from the factory but these are normally assembled on routine wiring loom

could happen but would be likely shooting more than just the once on a short

sounds like a short but the gun is all plastic - even motor plate and stock tube

so the pin is only place a short might take place I think

but even then it would probably happen more than just 1 shot

 

Think it was a freaky fire on full retraction that just slipped off the very last metal tooth if I'm honest

 

See how it goes - I doubt if it could happen again- if it does then it needs investigating or exorcism

[M4freak]

there hasn't been any "incidents" since then, all that has been done to it is a new paint job, new muzzle.l break, started using a pmag rather than use the cheap m4 mag that came wth it, I also swapped the sights. The ones on it now are just some standard mp7 sights, just because it was all I had lying around