Hopup problem?

[byblos]

hey guys, i have a Prometheus Air Seal Chamber Packing (Soft Type) inserted into a King Arms AK Hop-up unit attached to a Mad Bull 6.03mm Tightbore Barrel - 455mm...

when these are all put together i test out the hopup unit by pointing at a lightsource, i can see a nice bump when the hopup adjuster is at its max.. so i put the gun back together, carefully, making sure i dont move/twist the inner barrel. when i test out my rig, i will not receive upwards hopup arc at all, non what so ever.. its a good thing right? but i still do not get an upward arc when the hopup adjuster is at its max... i took it apart, checked the inner barrel pointing at a lightsource, and still having that nice half circle or whatever. gun does shoot at average 390 FPS.

so what is causing this??? is this normal???

[The Saint]

You sure your hopup nub went into properly?

[byblos]

the very tiny rubber tube? yes.

the placed it onto the hopup's curve, placed the hopup adjuster in, still have that nub in place. i insert the barrel with sleeve in, and tested to see if i get a bump.

[Ktown Militia]

i'll send u vid on a how to I made.

[green_ninja]

Did you lube the inside part of the hopup packing? If you did, it reduces the "friction effect" which causes the spin for the hop up to work, especially when it's a soft type. Just wipe it dry on the inside and only lube the edge where it touches the innerbarrel and around the hopup unit on the outside for proper airseal.

Another mistake some people make is not aligning the packing with the innerbarrel. There's a small groove that runs parallel along the tip of the innerbarrel which matches the inside of the packking.

Always test the hop up with it completely off then slowly increase it by small increments.

let me know what you got.

[byblos]

thanks for the info, i didnt lube anything but inside the mechbox. and sadly i live in the city i cant test until sunday games

[byblos]

Originally Posted by green_ninja

Another mistake some people make is not aligning the bucking with the innerbarrel. There's a small groove that runs parallel along the tip of the innerbarrel which matches the inside of the bucking.

this is something i triple checked, and i have it inserted correct

[green_ninja]

cool beans, *pat on the back

[green_ninja]

I think the soft hopup packing is for anything lower than 320-350fps. Since you're shooting 390, do you have a hard type to try out? It makes sense when you think about it, harder hopup packing creates less of a curve and more of a depression giving more surface area for the bb to spin/drag on.

mspaint ftw!

[Skladfin]

how big is the bump?

If it's small, there isn't enough hop.

If it's big and still does it, it's either your BB is too heavy or the hop up rubber is lubed up/oiled up

[byblos]

i use .20 bbs, i will clean the hopup/inner barrel/rubber before the next game. i will also check whether i am getting a small bump or large.. not sure exactly how i will check this, but ill try

edit: how would i go about cleaning those things? if you say soap, that excludes the barrel right?

[Skladfin]

If it doesn't overhop with 0.20g BBs, it's obviously an assembly mistake somewhere.

get the hop up unit with the barrel out.

Dont disassemble anything, just look inside the barrel from the hop up side with the hop up set to max. A big bump would be like 2mm ish.

Check for assembly mistake first. Clean it only if you're sure that it's the oil that's causing it(And yes, just the rubber).

[byblos]

alright thanks. i will take it apart tonight, and take a picture showing the size of the bump. post it up and see what you guys think.

[Schlyder]

was the little nub inside the hopup, a really soft rubber?? I just did the same thing today. I didn't like the size of the bump when I turned up the hop, thought it was too small. I replaced the soft little rubber nub with a piece of harder plastic ( cut a little piece off the end of a pen's ink refill) Now when I turn up the hop I can see a bump, and it looks 100% golden. That might help you, sounds like the same issue.

[Kos-Mos]

You can also take the hop-up and barrel assembly out, place it vertical with the hop-up in your hand and the barrel tip towards the ground.

Place a BB in the barrel. If t falls right throught, there is a big problem. Either assembly or missing part.

If not, take a small rod or even your cleaning rod and push on the bb to make it pass the bump. It should not be VERY hard, but you need some pressure to make it through. If that is the case, your nozzle might just push the BB too far and past the bump when loading it.

I don't know if you understand, but anyways. I did that trick to find why I have repetitive jams in my L96. Found that it was bad BB quality, but anyways.

*edit* That rubber should be ok. The Prometheus hard type is for 450+ rifles. I used that in my L96, shooting from 450 to 700 fps. At 450, the hop-up was set a hair from zero.