URGENT! Hop up unit is not working correctly as should be.

[CaptainH]

My old hop up rubber had ripped and was not working so I decided to buy a new one which is worse than the old one.

It wont allow any BB's to come out and it just clogs up the gun.

They where labeled as "madbull 60 degree shark hop up rubber". As it states from where I bought it, it has 3 fins on the inside which indeed it does. I tried take a picture as best I could to show what it looks like.
Could these "fins" be the problem for which is stopping it from working?

The sort of raised part on the left is what one of the fins look like.

I have now realised that it is not working with the magwell in. I know this wouldn't have been the appropriate thing to do but say if I drop a single BB in between the hop up chamber and the air nozzle with out the magwell it seems to shoot fine, but with the magwell in it all clogs up and does not fire.

Now discovered that it works with the magwell in but does not work with any magazine that I have. Any ideas?

View attachment 10029

 

[Rock-climby-Dave]

what do you mean 'magwell'

What rifle is it fitting in?

Is the rubber getting caught up/stretched as you fit it into the hop unit?

 

[CaptainH]

what do you mean 'magwell'

What rifle is it fitting in?

Is the rubber getting caught up/stretched as you fit it into the hop unit?

Click to shrink...

This is going in to a JG SL8. What I mean by magwell is the actual magwell. Where the mag fits in. If I drop a BB in and down in to where it fires from (between the air nozzle and hop up chamber) it works fine but if I load a mag in it will not fire. It just jams up. i don't think it is caught up because before I put the gun back together it looked all clear down the barrel.

 

[Rock-climby-Dave]

ah, never thought of a removable magwell!

Have you got any other mags from other guns you can try? If you hold them against the feed tube, they should feed fine. Alternatively try a speed loader whilst pushing BBs into the chamber.

 

[CaptainH]

ah, never thought of a removable magwell!

Have you got any other mags from other guns you can try? If you hold them against the feed tube, they should feed fine. Alternatively try a speed loader whilst pushing BBs into the chamber.

Click to shrink...

I have tried Kingarms mid caps and JG hi-caps. Both with the same problem. I have been told that these buckings will not work in all guns and are meant for some special sort of gas gun. So that could be one of the problems

 

[Rock-climby-Dave]

AFAIK Madbull only do the shark buckings for AEGs. Do you have a link to the bucking you bought?

 

[Ian_Gere]

Did you do anything else to the gun while it was broken down other than change the hop rubber? I ask because having a mag in or out should not make any difference unless the hop unit is loose, so that fitting the mag shifts the feed tube (that bit that BB's go up into the hop chamber), so that could be the problem right there, unless you did anything else...

Shark buckings can be a bit of a pain in the arse. I've fucked one up getting it back out because BB's wouldn't fire with it in and had mixed results from another (although that is in an Ares gun which is a known basket of arse, so the problems may not be down to the rubber entirely or even at all). I'm pretty sure Ed takes a pretty dim view of them too.

 

[CaptainH]

Did you do anything else to the gun while it was broken down other than change the hop rubber? I ask because having a mag in or out should not make any difference unless the hop unit is loose, so that fitting the mag shifts the feed tube (that bit that BB's go up into the hop chamber), so that could be the problem right there, unless you did anything else...

Shark buckings can be a bit of a pain in the arse. I've f*cked one up getting it back out because BB's wouldn't fire with it in and had mixed results from another (although that is in an Ares gun which is a known basket of arse, so the problems may not be down to the rubber entirely or even at all). I'm pretty sure Ed takes a pretty dim view of them too.

Click to shrink...

I didn't touch anything else except the hop up and barrel. Everything else was left alone.How could I check if it is the problem with the feeding tube? What you have described sounds like it could well be the problem.

 

[Ian_Gere]

Best bet is to find a good disassembly/reassembly vid, but in the limited time I was prepared to devote to searching I could only come up with this JG G36K one which actually shows the hop/barrel assembly up close (at about 8mins). Might be best to have a look at a few more, just to familiarise yourself with what should be happening.

After that just take it apart and put it back together again, paying particular attention to making sure that nothing appears to be ambiguous about where it should go. The main things I'm thinking of here is that the barrel should fill the rubber right up to the end where the smaller diameter bit is, but not stretch it, and fit into the hop unit so that the perpendicular grooves go right up to the rearmost edge of the space in the hop unit for the C-clip. The spacer ring should go up against the rubber and completely inside the hop unit so that when you pop the C-clip back on, the raised straight bits fit snugly into the barrel grooves, locking the barrel in place. Inside the hop unit itself you have to make sure that the nub (that tiny cylinder) goes in exactly perpendicular to the barrel and that the tiny push-rod bit that presses down on the nub has its lip engaged with the inner part of the ring (please gentlemen, please). Also don't forget the spring which goes around the barrel - it is necessary for keeping the barrel tightly in place.

It's also the case that problems like these do not always seem to have an obvious explanation and simply breaking the gun down and reassembling it can sort out whatever the gremlin was/is. Feel free to ask for more details and/or embed photos to help you describe what you mean. Somewhere in the world, sooner or later, there'll be somebody else with the same problem so if we can solve it comprehensively here, that'll be our good deeds for any such day :lol: