Hop up

[Airsoft-Ed]

I know hop is something everyone will understand and have discussed in length 1 million times over, but I'm talking about the fitting here and how much difference can really be got for different nubs and rubbers.

There's also a problem that's been bothering me for ages and I want to see if any of you have noticed it as I have.

My hop unit is quite a tight fit, so as I push the barrel in, the rubber gets pulled really tight and spreads out at the bottom because of the pressure. Kinda like when you squeeze playdo and it escapes through the holes in your grip - except on a lesser scale.

The result, is that when looking down the barrel from the hop end, it looks to have seated perfectly, but if you look from the other end, you'll see bits of the hop bucking's 'skirt' I'm going to call it, protruding into the barrel.

My understanding is that this skirt protrusion is what stops BBs just rolling out of the barrel, which means that when you're not shooting, the BB in the chambre is sat behind, or inside the grip of this skirt.

Often in my hop, because of the squeeze, there's a lot more skirt protruding at one side of the barrel that the other and I can never get shots to fly perfectly straight. So I think that off set skirt protrusion is the culprit.

My issue is, that it's almost impossible to get an even spread of the skirt on all sides of the barrel, I either end up with loads on one side and none, or at least less, on the other.

I think it might act like a separate unadjustable hop, put a slight spin on the BB in the direction that the protrusion is at, before it then gets caught by the actual hop protrusion. Causing the BB to spin erractically as it tries to battle the spin forces in two simultaneous directions.

On the whole it isn't a problem, but sometimes I'll just see shots fly bang straight for about 40m, then fly off at random as if they were hit by something - always in the same direction.

The effect can change on every shot because the BB won't always catch the skirt the same, it depends how far behind it or into it the nozzle pushes it.

Does anyone else share my hop-skirt woes?

I tried shaving the skirt with a scaple knife to make it shorter, but I just ended up making my gun double feed because the skirt wasn't holding the first BB strongly enough to prevent the mag pressure forcing another one in behind it. (And ruining a hop rubber)

It's a god damn right pain! It's the only thing I ever have bother with and it makes me want to avoid taking my gun apart to avoid having to do it again, but because I'm a perfectionist, I just can't help but try and I just end up on a never ending quest for perfection, sometimes I just end up making it worse...

I'm starting to wonder if it's not just all in my head or something...

I'll let the debate with regard to nubs and rubbers unfold naturally, but right now I need someone to say "Yes, I know what you mean" lol.

The hop and nub discussion though, I know you can buy rubbers that are at different angles, with one or two protrusions and multiple different shape nubs, so I just wondered what everyone's verdict is?

We could try and build up a database of: Gun - Hop unit - Hop rubber angle and number of contact points - Nub shape used - Velocity of weapon - Range achieved (must be accurately measured and across flat ground with no weather conditions)

I know it's a tall order to ask for all that, but if we could get all that data down, we could find the best combinations for a lot of guns and help just about everyone get better range.

 

[RR01]

I've noticed this happen a few times as, once the barrel and hop are fitted but before I insert the nub and hop arm, I always look through the barrel from the muzzel end towards a light source to check that it's all sitting in the hop unit correctly and the the pad on the hop rubber pushes down square within the hop. If I find it's sitting too far in or at an angle, showing the distortion you described, then I'll pull it back out and try again, usually using a small squirt of silicon oil on the outside of the hop rubber to ease it's passage into the hop unit.

I've actually found this happens more often with Madbull hop rubbers, especially if also allied with a Madbull Black Python V2 inner barrel. I'm not sure if it's the distance from the gearbox end of the inner barrel to the cut-outs for the C clip on these barrels, but they seem to be more of a problem than others I have, both OE, Systema and Guarder. I know I've had to cut a couple of mm off the front of some rubbers to get them to sit in the hop properly with enough clearance to fit the C clip. There are also definitely differences in the length of the hop rubber depending on manufacturer.

One way I tried with one hop unit was to push a spare air nozzle into the end of the hop unit, at the same time as inserting the barrel & hop rubber. This ensured that it sat square and air tight once it was inserted. If you don't have a spare nozzle you can always push the hop unit on to the end of your gearbox, as presumably if you are changing barrels and/or rubbers then the receivers will already be split to allow access to the hop unit.

 

[Airsoft-Ed]

The nozzle thing is really the most excellent idea I've ever heard. I shall certainly give that a go next time I take it all to pieces.

The beauty of my L85 is that it's so easy to take the gearbox apart due to being able to remove the spring before opening it up that I won't even need a spare nozzle, I can just use my actual one that's in the GB and then reassemble everything in around 5 minutes.

=D

Cheers for the tips and I'm glad other people have noticed the issue as well. After posting that I actually managed to get it sat pretty good, it's still a little off-set but the gun's shooting great.

The rubber and nub debate can now begin!

I use a madbull blue and an H nub in my L85.

Reason? Everyone always raves on about the madbull blue but with standard nubs I think it's about the same as a stock bucking, in my experience. So I got an H nub, because then you're putting two points of pressure at either end of the bucking, which makes it protrude into the barrel at the same uniform level, because the H shape of the nub and U shape of the bucking cancel out to become flat. Which gives much better lift, more precise adjustments and means that when my hop is off, the hop is actually off! If I use a standard nub in conjunction with a madbull blue then the effect essentially, is the same as having hop on fully all the time, so it's useless.

I'd quite like to get one of those bucking that already have two points on contact, like fangs, though, just to try it out, 'cos I imagine the effects are similar to having an H nub, without needing to have an H nub lol.

Interestingly, I was working on my mate's AK just now and the stock nub actually is an H nub already, it looks exactly the same as the black one you get if you order a Big Out H nub, which are like £10, so considering it's an APS AK, I think that's phenomenal! H nub + stock rubber seems to be a seriously epic combination if this AK is anything to go by.

But then there are guns that are amazing anyway, the G&P CQB M4 I got for my brother, for me to make into an L119 almost matches the range of my L85 when it's entirely stock! Which is the most depressing thing in the world, when it cost about a sixth what I've spent on my L85.

I guess the science of hop units might just be one of those things that physics just can't explain... 'Cos I sure as hell can't understand why two guns with the same parts can behave entirely different, it makes no sense!

 

[RR01]

I've found a few problems using Madbull rubbers. I've got an M16 that was upgraded by the previous owner with a Systema barrel and a Madbull Ultimate hop unit and which I use mostly as a DMR, as I've got a mosfet on it that only allows 3 round burst on Auto, if I need a little bit extra firepower. It started to get a little swing on the BB at about 50 yards and, as I had no idea what the original hop rubber was or how long it had been there, I changed to a new Madbull Shark Clear rubber.

Big mistake. From being able to take out people sticking their heads out from behind cover at 50 yards or so it started swinging the bb left at about 30 yards, with no real consistency, so straight,up, short, left, etc. I gave up with it after trying various nubs and hop pressures (I always use 0.25s in AEGs) as nothing made it better. For a trial I bought four FALCON Double Point Hop Up Rubbers (55 degree) from Ehobbyasia. I've put one in the M16, another in a Heinz M16 I made from parts and one in my second L85. So far I've only got to try them out in the Heinz M16 and the L85, but results were quite stable, especially as the Heinz has an OE inner barrel and the L85 has a Madbull BP V2 6.03. I'll try the upgraded M16 at F&O Asylum in a couple of weeks and hopefully it will improve as well, once the rubber settles down.

I know what you mean about L85s. My three are all ARMY, but with upgrades to the gearboxes using G&G parts they're all running fairly well now. My L85A2RIS looks a lot like yours (seen the pics on the other forum's L85 thread) but has a Madbull BP V2 6.03 inner barrel, a TM hop rubber and standard soft hop nub it and shoots beautifully. I've tweaked it to be very accurate out to at least 40 yards and as it's also got quite a quiet gearbox, I find people just don't hear the plastic death heading their way, especially as I tend to run the L85 on semi almost all the time (using midcaps means I don't need to mag change that often on semi), so no long motor noise.

The Falcon hop rubbers were only $7 each and with shipping I think I only paid about £16 for all four. Worth a try at that price.

 

[Airsoft-Ed]

Yeah definitely. I'll be looking into it once I get paid.

So what other combinations have you guys found to be effective? More than just RR01 must've read this thread by now!