Specna SA-C12 CORE not feeding. Now gearbox rebuild.

[Lozart]

Thanks for all the information.  I am thinking about a new nozzles as there doesn't appear to be an O-ring in there, nor a groove for it to live.  I have a micrometre which was a god send for sorting out the packet of shims - although there were a couple that were neither one size nor the other wen compared to the packet listing.

As far as I know the timing delay plate was OEM.  The only other person to work on it was Cage Airsoft, and I think I only paid for a new inner barrel, bucking, nub and shimming.  The new gear set were the Specna 16:1 from Patrol base, so hoping it is matched to the Specna piston.

The spur gear was the only one that wasn't stripped of teeth so I have kept it.  I haven't counted the teeth, but I think it was a 16:1 set in there, so should be OK to go with the other two gears?

Currently trying to resist the urge to by a Chrono now - but with 13 guns between me and the boy, I think I have enough potential tech work in our collection to justify it LOL.

More than likely the original gears were 18:1 but 16:1 shouldn't be an issue as long as you use the whole set.

Absolutely buy a chrono if you're going to be working on your own guns though. Way back when I was rebuilding my first gun (an ancient TM M4A1 that is still going strong albeit with less original parts than Triggers broom) I managed to get SUCH a good airseal that even an M90 spring put it over the 328FPS limit for The Mall! It actually has an M85 in there now.

 

[Dan Robinson]

Yeah - ended up order this one https://www.ebay.co.uk/itm/144019574727  which i think @RostokMcSpoons  also has.

Not sure what the weird plate is with loads of holes and numbers, but I'm sure it'll be fine.

I now have to look at the boys M16 which is not feeding.... Stand by for a separate thread on that one ?

 

[RostokMcSpoons]

Yeah - ended up order this one https://www.ebay.co.uk/itm/144019574727  which i think @RostokMcSpoons  also has.

Not sure what the weird plate is with loads of holes and numbers, but I'm sure it'll be fine.

It comes with a set of short poles that you screw into the plate, these fit around the suppressor / flash hider / end of the barrelso so that the BBs fly down the middle of the tunnel.
The number relate to the diameter the pins fit around, so it's a bit of a pain in the arse to change them around.  Best approach is to set it for a suppressor or flash hider you can easily swap between guns, and leave the pins on the chrono alone.   Unfortunately I found that a) even that takes too long for an impatient person and b) suppressors don't fit all guns

So if you're a lazy git like me, you just hold it up to the end of the barrel and try your best not to shoot the shit out of the inside of your new chrono

I've done that a lot now, and I'm considering an upgrade to something with a wider hole that I can shoot into...

                                                     View attachment 100909
View attachment 103664

 

[Dan Robinson]

 

[Rogerborg]

When you say 'him' I'm guessing .... Luke?

Nah, Roger was talking about Roger in the 3rd person, like the athletes and rappers do.

Then decided to augment the piston oring.... Which was looser than a wizard's sleeve.  So just to piss Mr Luke off, I carefully (because I'm a plumber and spin this stuff out of my rear orifice) wrapped ptfe in the groove of the piston Under the oring.

Heheh. Roger... I mean I assumed the same thing the first time, and packed silicone grease under mine.  It was only after thinking "Wait, what are those holes for" that I figured it out - oops. You can even drill some more if you're feeling frisky.

Now I stretch o-rings over the outside of the cylinder, and heat them gently, specifically to make them loose.  It's a bit hit-and-miss but now that same CYMA that I messed up has rock solid air-seal and hit 1.3J on an M100 spring using the stock CYMA gearbox and no-O-ring nozzle (and some aftermarket bits downstream of that).

Currently trying to resist the urge to by a Chrono now

No need to resist, it takes most of the guesswork out of it - although guns can of course run hot and cold on the day.

 

[Dan Robinson]

I'm half expecting the fucker to suck the bbs back up the barrel now LOL. 

 

[Colin Allen]

Yeah - ended up order this one https://www.ebay.co.uk/itm/144019574727  which i think @RostokMcSpoons  also has.

Not sure what the weird plate is with loads of holes and numbers, but I'm sure it'll be fine.

I now have to look at the boys M16 which is not feeding.... Stand by for a separate thread on that one ?

They are nice little chrono's.  I keep one in my game day bag for quick checks.

 

[EDcase]

I'm half expecting the fucker to suck the bbs back up the barrel now LOL. 

Hope not.  That shit gets messy