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Tight bore barrels!


Adammd209
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Tight bore barrels... Are they really worth it? I have a VFC HK417 and it's got a 6.04 barrel already as standard. Would fitting a tighter one really help with accuracy and distance? Also has anyone had any experience with Mad Bull BB's?

 

Cheers

 

Adam

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A tighter one will increase power,quite vastly in some cases but won't necessarily increase accuracy. A better made/machined barrel will give some performance benefits.

 

VFC barrels and hop up units tend to be pretty mediocre. A well made barrel will give an increase in accuracy and thus effective range. I like 6.05 bore barrels,6.03 are good too.

 

I always recommend Prometheus and PDi barrels. Both are really well made and popular choices and have proven to be consistent in providing good boosts in performance. Pricey though,however you can save some money by ordering from Japan where they are made. PDi have a distributor called Xfire which I've used a fair amount of times to order VSR 10 parts and I like their service.

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If you want additional accuracy without affecting FPS, your choice of rubber and nub combination is the thing to look at. If you think about how the system works, ordinary nubs are plain cylinders of varying stiffness which press the rubber down through the barrel window. So when the BB get's pushed past it by the compressed air, the top of the sphere is squished against the rubber. But the BB is not an exact tight fit in the barrel...

 

Decent BB's are manufactured to size 5.95 +/- 0.01mm & 6.01mm is a very tight TBB = approx 0.025mm either side as a best case. Not much, eh? Well if you imagine that slightly fat BB leaving the muzzle and moving 0.025mm to the left in, say, half its diameter 2.98mm, then @50m (50,000mm / 2.98mm = 16778.52348993289) that best case (x 0.025mm) becomes 419.463mm, ie compared to aiming at the centre of a standard man sized target 600mm wide, a miss.

 

It is much more complex, because rather than the maximum physical distance which a BB can move off-target within the barrel, how the BB spins when it is on its trajectory will be much more important to where it finally ends up. But consider the BB squashing past the rubber... what is to stop it being pushed completely to one side or the other? In fact, due to all the pressure involved, if there is any space the BB can move into, why wouldn't it? And it does. So now consider that the rubber is squidgy, so when the BB passes under it off centre, more of the rubber squidges down around the side opposite to the direction of movement off centre, which makes the hop effect off centre.

 

There are two methods to combat this which both work in the same way but, as far as I am aware, are mutually exclusive: H-nubs and split bump rubbers.

 

H-nubs (also called X spacers, X-nubs and fishbone spacers) work with standard hop rubbers / split bump rubbers need to be pushed down by ordinary nubs. The principle is that by controlling how the rubber squidges, it forces the BB into the centre of the barrel and the hop effect will be applied evenly.

 

H-nub / gucci H-nub / PDI W-hold rubber / Falcon Dual Point rubber

 

You can't buy CYMA hop rubbers on their own, afaik, but many ppl look down their noses at such cheap stock parts - if you meet anyone who wants to upgrade their new CYMA gun with a new rubber, buy the stock one if you can. They have a simple split bump which opens wider the more it is squashed; it works very well.

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Good info above. All of which are plug n play solutions. If you wanna go DIY then look into G-hop and R-hop.

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R-hop is for lifting heavy BB's though. In any gun which can make the BB weight you choose for that gun's muzzle energy rise too much, no matter how cold it is, it will be completely useless.

 

I don't know much about G-hop. From what I do know, it's about introducing a tiny degree of additional consistency to the amount of hop applied, by adding a spring to press on the hop unit arm. Obviously this only works with certain hop unit designs. Those in which the amount is dialled on with an eccentric collar, like in a G36 or the airsoftpro.cz Advanced Hop Unit for A&K Dragunovs, don't have an arm...

 

TBH, the reason I haven't bothered to find out more about G-hop is because the claims I have seen are frankly ridiculous. There is no hop tweak on earth that is going to make a 1 Joule muzzle energy gun fire 80m accurately enough to even hit a man sized target consistently, let alone get a grouping on a 600mm wide target. I mean yeah, with the right set up you could lob 1J shots that far and walk them onto the target, but they will be travelling so slowly at that distance that they may not be felt and also the slightest disturbance of air, literally a good fart's worth, would be able to push them significantly.

 

What I don't understand is why flex in the hop arm should be considered inconsistent from shot to shot. It's the same hop arm and, whether we consider it simply in the vertical dimension only or include the three dimensional torsion which it will undergo, for any given setting the only variable is the degree to which the upward pressure which results from the BB squashing the rubber and nub is off centre, which is a function of where abouts the BB is, from side to side, as above. Even if we were going to consider an unlikely but possible abrupt severe temperature change, most AEG hop arms are plastic: poor heat conductors. I think that if there is anything to G-hop, and i'm not saying there isn't, the difference from one shot to the next can only be so little as to be only useful to snipers, where even the minutest inconsistencies will be translated into centimetres at their longer ranges.

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I've fitted my new barrel and bucking and after a few teething problems seems to have improved the accuracy slightly.

 

I've ordered one of the H-Nubs from eBay, so let's she how she does with that.

 

I will get back to you with my opinions.

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What brands did you go for, Adam?

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I think you may have confused Ghop with another thing Ian.

 

Ghop is essentially the same concepts as Rhop,using a patch to apply hop to the BB instead of the usual nub inside a standard bucking. Ghop however uses a cut up flat hop up rubber as a patch instead of pre-made ones like R-hop patches. Ghop came a bit before Rhop came around(I think) It was first seen on Gunjineer.jp I believe.

 

I'm yet to try Ghop since I'm finally happy with my VSR's performance but when my PDi W hold wears out(Which will take I fairly long time I'm sure) I'll defiantly try G hop and if I buy some more W hold along the line may try out flat hop too,and compare the two mods.

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Thanks Alex. Still not much use to UK AEG's though, eh?

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Thanks Alex. Still not much use to UK AEG's though, eh?

It depends on the player. If you are a whore to have the best gun you can possibly have then it might be useful. If you want to have a DMR or bolt action rifle then it's very nice to have as it does give a noticeable performance increase and having good accuracy is crucial since you are heavily restricted by rate of fire. A youtube user called Top hat runner has had very good results from G hop on his realsword type 97. Ghop and Rhop are especially useful for lifting very heavy BBs(.3s are the lightest weight that can be used effectively according to some guys)

 

Like I said,really depends on the person. I personally think it's no use having a hyper tuned gun but being a poor player,I've seen lads with 30+RPS AEGs and fancy R hop get reck'd by a lad sneaking through a trench with a 150 euro china AEG that sounds like a dying cat when fired.this is why I'm laying off all the upgrading on my gun to practice movement,awareness, shooting and general combat stoof,and maybe just forking the whole sniper optic thing and going for a Simo Hayha route. I'm decent enough to sneak up to people but I'm hindered in quick aiming by a scope.

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Eye relief becomes the issue then, unless you're using an optic with very very low magnification or specifically designed to be forward mounted.

 

As for all the various hop mods, I call snake oil on a lot of it. A good bucking and nub with a decent firm hop-up unit is all someone really needs.

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Too much work with JB weld. I'm thinking of getting some MP7 sights or RIS mounted and placing them on the rail,Should be usable enough. CBA getting a TM/JG front sights and I don't like the way the VSR style front sight is tape on.

 

Might even keep the scope and have the pistol/MP7 sights under it as backup.

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