The hop unit...

[Airsoft-Ed]

Ok, riddle me this.

My L85's hop unit is magic, in a bad way.

It's shooting at about 310fps with .25s and even when the hop is COMPLETELY off, they STILL fly upwards. When I say completely off I mean that not only is the wheel showing that hop is off as far as it can go, but also, after stripping the gun and looking down the barrel, there is nothing protruding into the barrel at all. The lining of the hop bucking isn't even protruding into the barrel if you look down it from the muzzle end.

The amount they fly up by isn't that bad in all honesty, it gives me a good 60m range.

However, if you imagine shooting across trenches when the person you're aiming at only has their head showing and they're on the exact same level as you, the hop makes it impossible to hit them, because to compensate for it, you have to aim down, but given that situation, aiming down will result in hitting the ground and never getting your shots anywhere near the target.

So what have I tried so far?

Well I've tried putting the hop on to the extent where it blocks the barrel and causes the BBs to drop, but that doesn't work, they just fly up even more. Which is mostly due to the fact that the hop bucking is too stiff for the spring that pushes the hop arm down to be able to put the hop on more that a certain amount, in effect meaning that the most the hop can be on, is about a third of the travel distance available.

I've also tried completely removing the nub and the hop arm, which caused the BBs to drop after about 20m.

I'm out of ideas now. It just goes from one extreme to the other.

It seems that I'm left with one of two options, leave the hop assembled fully, but turned completely off and deal with the shots flying up by about 1m , dropping back down into my crosshairs at somewhere around the 50m mark.

Or have the hop completely removed and deal with having so little range that I can't use my sights because I have to aim so far up that I lose sight of the target through them.

It's god damn annoying.

Has anyone else ever had a similar experience? What would anyone advise to remedy it?

I don't really want to use heavier ammo because the fps isn't high enough for it to be beneficial, I'd also like to keep the fps the same, so I don't want to lower the tension on the spring, or fit a weaker spring.

I guess the only way I can go from here is to change the bucking or the nub for lower profile ones, but I spent about £25 on the hop parts and it seems stupid not to use them after spending that much...

Sigh...

Apologies for the wall of text.

 

[Hudson]

What bucking and nub have you put in currently?

 

[Airsoft-Ed]

I've got a Madbull Blue bucking, I think it's 60 degrees.

And the nub is a Big Out H nub.

I just tried using a stronger spring for the hop arm, see if I could grab a bit more than a third of the full travel. It did give me more travel, but the BBs just keep flying up and up and up... <_<

 

[rschris]

you have got the madbull in the righht way so the nub is permitted to do its job?

take out the barrel and move the hop see if it moves.......

 

[REMSoft]

I had a similar problem with one of my pistols, overhopping .3G bbs using 134a! To fix it, I bent the hop arm, giving it a smaller contact face with the rubber. In your case, I would suggest switching to a standard Marui hop rubber and non h-nub bucking. It's just a case of your hop unit being too awesome for your gun! :lol:

 

[Airsoft-Ed]

you have got the madbull in the righht way so the nub is permitted to do its job?
take out the barrel and move the hop see if it moves.......

Yes I do, I'm not an idiot lol

I know this gun like the back of my hand, the hop bucking doesn't even fit in the unit if it isn't all put together right.

I had a similar problem with one of my pistols, overhopping .3G bbs using 134a! To fix it, I bent the hop arm, giving it a smaller contact face with the rubber. In your case, I would suggest switching to a standard Marui hop rubber and non h-nub bucking. It's just a case of your hop unit being too awesome for your gun! :lol:

Too awesome... Well that sounds about right.

It seems a shame to not use the upgraded nub and bucking... I might try the stock bucking and the H nub, see if that helps.

 

[Airsoft-Ed]

Bump... Sort of. Want to keep people replying.

I just tried fitting the stock, black hop bucking and the H nub and the results were... Well, still not what I want.

When the hop dial was off, hop was indeed off, to the point where they drop short at 20m - all good so far.

Increasing the hop did indeed increase the hop. However, my shots weren't flying straight until the hop was on about 2 thirds of its full travel and by this point, the hop was also reducing my fps so much that the shots were flying less distance than they would go if the hop was on less and my shots were dropping.

Still stumped.

When it's light enough to test fire again, I'll try the Madbull bucking and the stock nub, then the good ol' biro-ink-thing-nub and see what happens then.

This is kind of one of those problems where you wonder if it was just always like this and you've only just noticed it, kind of thing.

If anyone else ever gets that feeling about stuff?

 

[Airsoft-Ed]

Update.

I tried changing the hop nub over to a few different ones, the stock nub, the ones supplied with the madbull rubber and the biro tube hop mod, all of them still resulted in crazy over hop.

I did finally manage to get the shots flying straight, but I had to remove my twist barrel and stick with a regular Madbull tight-bore. Thankfully the hop is über-tastic enough to make up for the range drop from using a crapper barrel, so I can still get crazy range. Accuracy isn't quite as good, as the barrel doesn't help with hop inconsistencies but it'll do for my next couple of skirmishes.

Once the hop bucking is bedded in a bit better I'll change the barrels back over and see if it helped at all.

Unless anyone has any other ideas?

 

[Ian_Gere]

How does a twist barrel work? In the obvious way, ie like rifling? Cos I'm buggered if I can understand how hop works at all if the BB exits the barrel with perpendicular angular momentum...

 

[Airsoft-Ed]

I'm not really sure how they work to be honest, I think the theory is that they spin the air around the BB, meaning it hits the inside of the barrel a lot less as it travels down it, you don't need a lot of hop at all when you're using one.

They are actually rifled though, but the twist rate really isn't very high, I'd guess maybe one full twist for every 130mm, there's only about 3 twists of the rifling over the length of the whole barrel. They also apparently work their best when the gun is shooting 330fps or less, though in my experience it works more or less the same at any velocity, but I use heavier ammo to bring the fps under the 330 mark anyway.

Not sure how they work, but work they certainly do, I'd say mine gave me about a quarter extra range when compared to a completely stock hop and barrel set up, or even a regular tight bore.

On the down side, they do cost about £75, which is why I'm a bit miffed I can't use it anymore.

 

[Ian_Gere]

On the down side, they do cost about £75, which is why I'm a bit miffed I can't use it anymore.

Yeah, I can see how you would be, mate! So... are you getting more range out of your madbull tight bore and gucci hop set up than with the twist barrel and stock hop set up?

 

[Airsoft-Ed]

It's about the same as far as I can tell at the moment, I'll have to skirmish it to know for sure, see if I can pull off the same shots as I'm used to.

The annoying thing about using the Madbull barrel is that to hit greater ranges I have to up the hop slightly, so depending on the range of the target, I'll have to make a lot of in-field hop adjustments.

With the twist barrel and gucci hop set up it was just, see a person and they're dead, no adjustments necessary.

The most annoying thing about all of this is that it was working completely fine with the insanely good hop set up AND the twist barrel last time I skirmished it, it's just the last couple of times I've tested it in the garden that it's decided to turn stupid and not work.

I've tried replacing all the parts of the mechanism that I can without altering the upgradable components and I can't get it shooting how it was last time I skirmished it. It's driving me insane.

 

[Ian_Gere]

Aha! So something must have changed... Is it possible that some lube has got inside the barrel/hop?

I can't come up with a theory as to why that would produce the effects you describe, but it seems a likely candidate for something that could have changed...

 

[Airsoft-Ed]

Aha! So something must have changed... Is it possible that some lube has got inside the barrel/hop?
I can't come up with a theory as to why that would produce the effects you describe, but it seems a likely candidate for something that could have changed...

I think the thing that changed was the strength of the spring in the hop unit, but I've replaced it with a spring from a pen and it didn't solve the problem.

I've more or less smothered the hop rubber and barrel with grease to actually get everything together, the hop unit is really tight so it's necessary, never caused a problem before so it can't be that.

It's got to be the spring, it's the only thing that changed. But it makes no sense that replacing it didn't sort the issue out. =[

 

[Ian_Gere]

That as well, but the 1st thing that's bugging me is how tf are your BBs rising when the hop is so far off that you can't see any of it obscuring the barrel?

This is 1 reason I started wondering if there's something else apart from the hop that is causing back spin on the BBs...

 

[Airsoft-Ed]

That's the thing that I really can't understand either lol, it really makes absolutely no sense.

Additionally, when I removed the hop nub, the BBs were dropping significantly, as they would if there was no hop on at all.

So in both cases, nothing visible down the barrel, but hop is either mega off, or on quite a bit.

See why I said it was the hop that defies physics now?! What the hell is going on?!

 

[Ian_Gere]

No clues me h34r: this is what comes of twisted voodoo barrels, young Skywalker...

Tell ya what though, I'd clean the inside of hop and barrel with soapy water 1st then polish with a dry soft rag...

 

[Airsoft-Ed]

I'll give that a go, not sure it'll help though.

I did think it could be something to do with the angle the gearbox was spitting air into the hop unit and barrel, but I've had it all to bits a million times and it only goes in one way, the gearbox is all solid and together right, the cylinder head is straight as an arrow otherwise my piston head wouldn't work properly and most importantly, if anything were misaligned, then the Madbull barrel would be over-hopping as well...

I'm sure I'll get to the bottom of it one day. It's a shame it takes so long to get the barrel and hop assembly out otherwise I'd feel more willing to keep trying it with different combinations of parts.

 

[SooGoo]

And after reading all this "the Joy of Airsofting" comes to mind