Hop up assembly help?

[Pleyland85]

Hi All,

I’m assembling my King Arms hop up unit and I’m left with a small rubber o-ring and an extra spring. Does anyone know what these are for?

Photo attached! Thanks 

View attachment 34274

 

[Hudson]

The spring looks like it's the one that goes on the arm itself.

Unsure about the O-ring, but I don't think it's essential. None I've used have ever had one.

 

[Pleyland85]

Thanks! You’re right about the arm spring. 

Just the small o-ring I can’t figure out ?

 

[Adolf Hamster]

isn't that o ring the one that goes on the end of the arm pin to stop it backing out?

i lost mine but it's not much of an issue as once it's in the reciever the arm can't back out anyway.