Need help urgently, Hop up unit

[seaneeng6]

Having some problems with my SHS full metal hop up unit, brand new.

In the picture it clearly shows the problem, any fixes? the gun just wont fire, but air is still coming out the end.

 

[Spatch]

It looks like your hop rubber and barrel haven't seated correctly, ie all the way in, very hard to tell from that angle, air will still go down the barrel as it comes from the nozzle not the hop

 

[seaneeng6]

It looks like your hop rubber and barrel haven't seated correctly, ie all the way in, very hard to tell from that angle, air will still go down the barrel as it comes from the nozzle not the hop

Click to shrink...

i have tried 2 different op up rubbers, neither seem to be working. i have tried pushing them further in.

 

[seaneeng6]

Just tried another barrel, still no luck.

 

[RR01]

Is the hop on too much, so that it's jambing the barrel? If you clear it out, then look down from the muzzle end towards a light source you should just see a very slight protrusion of the hop rubber into the top of the inner barrel, no more that about half mm with the hop fully off. Any more and it could be too tight. Also, was the barrel fairly easy to fit into the hop unit, or was it a very tight fit? I've had similar with one hop unit where the inner barrel (a brass one) and hop rubber combination (a Madbull Blue) was really too big to go easily into the opening in the hop unit.

 

[Ian_Gere]

I'm thinking that the nozzle may be at fault here. But it could also be barrel placement.

Is there a BB in the barrel behind the one we can see?

Is the C-Clip locking into the grooves on the barrel, with the groove at the rearmost edge of the window in the hop unit, and so the clip sits neatly in place, not protruding out at all?

Did you put any grease or oil on the outside of the hop rubber, once it was on the barrel, before you slid the barrel and rubber into the hop unit?

Have you had the gearbox apart?

Have you changed the air seal nozzle?

Are you sure that the tappet plate spring is connected?

Is the tappet plate front angled bit slotted into the groove on the air seal nozzle so that they can only move together?

Is the gearbox sounding different, with more vibration? Because if so the tappet plate lever end may be bent and not engaging with the cam on the sector gear properly.

A quick way to check these potential issues with the tappet plate and nozzle operation is to fire it while disassembled (the gun, not the gearbox lol) and watch the nozzle. Does it move back and forward ok with each shot? With it on full auto, can you stop it moving forward with your thumb?