Question about Hop Rubbers

[ru7hl355]

Now this is gonig to be a silly question to probably most people, but if you take a brand new hop rubber and sit a bb ontop of it what should happen.

A)BB will sit there till pushed through
B) it falls straight through.


Just asking because i just got a few guarder clears through and the BB's just fall straight through them.

and the one i have fitted to my PDW seems to have lost me 40 FPS

any help woud be appreciated

[ILLusion]

The Guarder clears are extremely soft... it needs to be mounted to a barrel inside of a hop up chamber to get the stability it needs to hold the BB in place.

Doing this test that you're attempting won't provide you with any valuable information.

If you MUST test like this, at least mount the hop up to your inner barrel inside your hop up chamber.

[m102404]

Just the hopup rubber? or the hopup rubber on the inner barrel in the hopup unit?

If it's the latter, the only thing stopping a BB from rolling down the barrel is if the hopup is on enough so that there is a bump blocking the path of the BB.

There's some areas where you MIGHT get an air leak with swapping out the hopup rubber.
- the inner barrel is moving back and forth in the hopup...thus moving the rubber back and forth...when it's away from the nozzle even just a bit, you'll get a leak. Either swap the rubber, swap the hopup or use a bit of teflon tape (thin plubmers tape for sealing screw fittings) so that the inner barrel/rubber is good and snug in the the hopup unit (I.e. so it doesn't move at all)
- the lips (the very edge of the hopup rubber) aren't positioned nicely and thus aren't making a full seal with the tip of the nozzle. Again, you'll get a leak. Pull the barrel and rubber from the hopup, reposition and try again. The rubber lips should be even all the way around in the hopup unit.
- it's impossible to set the hopup without a bit of distance to test...but with the hopup off you should see any (or very little) rubber protruding into the inner barrel...and as you turn the hopup on, you should see a nice even bump protrude more and more. Set it half way to start with and then BB's won't roll out the barrel when you're test firing.

You could also try to reseat your mechbox in the box...sometimes they can be torqued a bit and essentially the nozzle gets pulled away from the hopup. A good example of this is with an m4 where the stock pipe screws into the spring guide. Some guys really crank on the stock screw and it essentially pulls the whole mechbox back a bit.

Best of luck,

Tys

[ru7hl355]

cheers guys,

tested it in the hopup and its not falling through, just trying to figure out why its not feeding right, as my other hop and barrel feed fine(trying to setup a longer barrel for my KAC PDW).

i have ordered up a Prometheus Neo Hop Chamber and some madbull blue buckings so lets see if they fix it.

just really weird as i have fitted loads of hop rubbers and this has me stumped as to why its not feeding, i did notice that the Guarder hop chamber i have is only listed for m16's and not M4's.....

[ILLusion]

Shouldn't make a difference. M16 and M4 use the same hop up chambers.

Try swapping the hop up chamber that works from your other gun in to this gun (and keep everything else the same - barrel, rubber, etc) so you can at least narrow down that it's not the hop up chamber that is the problem.

I've encountered a couple of hop up chambers that were not moulded correctly inside and had to be reamed out.

[ru7hl355]

it is the same gun, im setting it up so i can switch between 2 diffrent barrel's when i need too so its got to be the hop chamber or rubber. hopefully the new one coming will sort it out.

[ILLusion]

So what I'm saying, is to use logic of deduction to rule out which part it is by swapping with the known working set, one part at a time.

[ru7hl355]

yep i get you, but the only thing diffrent is the hop chamber. there both in the same gun, same hop rubber, same brand of barrel....

so process of elimination says its the hop chamber no?

[ILLusion]

Originally Posted by ru7hl355

yep i get you, but the only thing diffrent is the hop chamber. there both in the same gun, same hop rubber, same brand of barrel....

so process of elimination says its the hop chamber no?

I think I'm confused as to what you've tried and what you haven't tried.

You have:

• Hop up chamber A
• Hop up chamber B
• Hop up rubber A
• Hop up rubber Guarder
• Inner Barrel Madbull A
• Inner Barrel Madbull B

Hop up chamber A, rubber A, and barrel A combined together are all known to work.

Is this correct?


What I'm saying now, is to use Inner Barrel A, Rubber A and Hop up chamber B together... if it works, then the hop up chamber isn't the problem. If it *doesn't* work, then the chamber is the problem.

Second, confirm the findings, by using Inner Barrel A, Chamber A, and Rubber B together to rule out the Rubber B.