VFC SCAR-L Hopup

[GBear]

Okay wow.

My curiosity is serious killing me and I am on a roll, breaking my gun down a little at a time. So, I was reading around and I think this is called the hop-up bucking. I accidentally pulled the inner barrel, trying to figure out how to take it out. Then I broke this little bucking seal thing. Any idea how to repair this? Do I have to buy a whole hop-up unit?

Sorry if the photos are horrible quality. I took the pictures with my Blackberry.

Broken Hop-up Bucking View #1:


Broken Hop-up Bucking View #2:


Hop-up:


Thanks for putting up with me guys!

[Thenooblord]

just get a new hopup rubber, they cost like $10

[Donster]

Originally Posted by Thenooblord

just get a new hopup rubber, they cost like $10

+1

Get a Guarder clear or Prometheus Soft and throw in a Shredder Concave Spacer for increased range and accuracy.

[Daiviet]

I TOLD YOU NOT TO OPEN IT UP UNLESS THERE WAS A PROBLEM.

lesson learned. Don't do it again.

hop up rubbers are available from airsoftparts.ca

[GBear]

Originally Posted by Daiviet

I TOLD YOU NOT TO OPEN IT UP UNLESS THERE WAS A PROBLEM.

lesson learned. Don't do it again.

hop up rubbers are available from airsoftparts.ca

LOL! I know! I know! But I was just sooo curious. The gun was staring me down! I couldn't help it. That's what I like doing though. I love taking things apart and checking out how they work. :lol:

What does the degree mean for the rubbers?

http://www.airsoftparts.ca/store2/in...roducts_id=804

Like this one. It says 60 degrees.

Also, what does that little metal piece do? It looks funny.

And how do I go about installing this thing? I would have to take the hop-up apart don't I? There's this really small screw that's blocking the hop-up from coming out. I've tried everything but I can't get it out!

[Danke]

I have the Guarder clear in mine, it's a perfect match for a stock VFC.

[voorhees -FWA-]

Originally Posted by GBear

Also, what does that little metal piece do? It looks funny.

That's the bucking... and they're rubber

[GBear]

Originally Posted by tte404

That's the bucking... and they're rubber

Oh okay. And the other thing is called the sleeve. Where does this little thing go?

[-Trooper-]

The Prometheus soft rubber is a very tight fit for the hopup

[voorhees -FWA-]

there's a notch on the arm that swivels on your hopup unit u can actually see the bucking in your second pic

[GBear]

Oh yeah that thing! Okay. That makes sense now. Do you guys know how I can put this all back together? What type of key or screwdriver do I need to take out the hop-up, I can't see inside the little screw hole even with some bright lights!

[voorhees -FWA-]

There shouldn't be any screw or anything there - the rubber goes on your inner barrel and you slide it into the hopup unit; make sure the bucking is in place and there should be a brass barrel spacer that fits in the front to center the barrel to the hopup unit

[Danke]

You need to use a hex wrench to pull the hopup chamber from the outer barrel. I can't remember the size but it's one of the smaller common metric ones.

[GBear]

Since I think I have a proprietary hop-up, does that mean I can't upgrade the inner barrel?

Originally Posted by -Trooper-

The Prometheus soft rubber is a very tight fit for the hopup

Is this a good or bad thing?

[m102404]

LOL...ok, I'll help since you were well behaved at the FR game.

You need a new hopup rubber (aka sleeve). Most will come with a nub (little cylinder of rubber...looks like wiring shielding after you strip a wire)....some don't. Don't toss the one you have...you'll need it one day.

The nub sits in the cup of the adjustment arm (in your last pic you can see the arm there). It lays horizontally...perpendicular to the axis of the barrel. When the arm is down, it'll push the nub against the rubber, which will cause it to protrude into the cutout in the barrel, which will then rub against the bb as it passes, creating back-spin.

When putting it back together, you're going to need to poke/prod that nub back into the cup of the adjustment arm. A small allen key is handy. Adjust the arm so that it's all the way up (relative to your last picture).

The rubber sleeve can only go on one way on the barrel. It should fit snug.

Have the hopup all the way up (this is Off)...then slide the barrel, with the rubber on it, into the hopup assembly...you might have to twist/turn it a little...go gently/smoothly. A little saliva on the rubber helps. It might be a very snug fit to get it in. Keep at it...don't mangle the rubber as you shove in the barrel...don't drop the nub out as you wrestle with it.

If it's a really loose fit...you might end up with an air-leak. Try a different rubber.

Once it's in...if you look fromt he chamber end you should see the lips (the first part of the rubber that a bb will touch when it's fed into the hopup) nice and even in the opening...if they're bunched, pinched, warped, whatever...you need to try again.

Once you think you've got it...look down the barrel from the muzzle end (look at a white wall or just off a light). You should see either no rubber protrusion into the barrel...or just a bit with the hopup off. As you turn the adjustment wheel, you should see a bigger and bigger bump come down into the barrel. That's working well. If you don't see anything show up...then you've either missed putting in the nub, or the nub/arm/rubber combo that you have in there isn't lined up right.

You can't adjust the hopup in your basement...you need a good 40'+ to see it kick in. For now, just put on enough hopup so that BB's don't just roll down the barrel on their own. You can test it before you reassemble by placing a BB on the lips...then use something none-pokey to push it past the lips....it should stop at the bump of the rubber. Then push it past the bump to clear the barrel. If you can push a bb past the lips with just minor/light pressure, that's good....if it requires a firm/hard push, you're likely to have feeding issues once it's reassembled. Try a different rubber in that case.

Soft rubbers are "sticky/grippy/tacky"...and so conform to the BB as it passes by, imparting lots of back spin. Hard rubbers don't do as much, but they'll last/wear longer. For sub 400fps guns I use a soft rubber (guarder clear).

Now that you know how to change your hopup rubber...swapping it out once a season or if you happen to tear it is no big deal.

NOTE: When you clean your barrel, you want to either take the barrel out of the hopup...or at the very least turn the hopup off all the way so you're not ramming the cleaning rod into the rubber bump.

Hope that helps,

Tys