One pew two bbs come out

[Pollynator_bravo2]

Evening all

so My CYMA CM.057B (Dragunov SVD variant AEG) randomly is firing out two bbs with one trigger pull. It was doing it after game day one with zero modifications done. I’ve checked the bucking and this is in next to new condition. I have added a M120 spring and on .25g it’s achieving 1.6j. I’m using cyma svd mid cap mags as the hi cap that came with it broke on day one and I thought originally that may have been the issue. I’ve seen about drilling a 6mm grove into the top of the hop to help hold a bb in place but is this a legit solution ?

[Cannonfodder]

What voltage battery are you using? Going too high with the voltage can cause over spin of the motor 

[Dan Robinson]

^^^^^^^^

 

This - my one double pews with 11.1v.

[Fatboy40]

5 hours ago, Cannonfodder said:

What voltage battery are you using? Going too high with the voltage can cause over spin of the motor 

 

... and to add to the above I'm assuming that there's no optical controller of any sort in the gearbox (monitoring the sector gear) offering "cycle control" so that it doesn't over spin / there some sort of active braking.

[Rogerborg]

17 hours ago, Pollynator_bravo2 said:

I’ve seen about drilling a 6mm grove into the top of the hop to help hold a bb in place but is this a legit solution

 

If it's a feeding issue rather than motor overspin, then yes, surprisingly, it did help[*] with double feeding issues on my MP5K after I'd meddled with it.

 

We're talking a small indentation. I ran a 6mm just a few turns forwards with gentle pressure, then in reverse to deburr it.

 

[*] Always assuming that it wasn't just another disassemble-reassemble which resulted in everything lining up properly.

[Pollynator_bravo2]

On 04/09/2023 at 09:40, Dan Robinson said:

^^^^^^^^

 

This - my one double pews with 11.1v.

I did use a 11.1v son gonna try a 7.4v tonight

On 04/09/2023 at 10:08, Fatboy40 said:

 

... and to add to the above I'm assuming that there's no optical controller of any sort in the gearbox (monitoring the sector gear) offering "cycle control" so that it doesn't over spin / there some sort of active braking.

No optical controller pretty basic insides tbh

19 hours ago, Rogerborg said:

 

If it's a feeding issue rather than motor overspin, then yes, surprisingly, it did help[*] with double feeding issues on my MP5K after I'd meddled with it.

 

We're talking a small indentation. I ran a 6mm just a few turns forwards with gentle pressure, then in reverse to deburr it.

 

[*] Always assuming that it wasn't just another disassemble-reassemble which resulted in everything lining up properly.

Ok I’ll try the battery and when I’ve exhausted everything I know that is an option. I’ve tried the take it out try again several times however it did it before I took it appart

[Dan Robinson]

May the BB overlords smile down upon your efforts. 😎

[Cannonfodder]

9 hours ago, Pollynator_bravo2 said:

I did use a 11.1v son gonna try a 7.4v tonight

Always best to try the simplest things first

[Pollynator_bravo2]

On 05/09/2023 at 20:35, Cannonfodder said:

Always best to try the simplest things first

Yeah that’s got the issue more under control. I need to get the power down now to 1.44j as I’m a bit hot at 1.62