[bobgengeskahn]

For those familiar with it, I have a few questions, mainly about the material that HS5 uses/what you think would work. Due to unexpectedly low funds, I am trying to occupy my time with more DIY mods and such that can be done for cheap and have been thinking about doing this to my SL9. I have a few ideas I might play with to change up the construction a bit, but for the most part I will probably keep it the same.

One question I have is: is there a spacer in the R-hop like there is in the G-hop? Or since HS5 uses a curved rubber does he not need it? I was unclear reading through his threads on ASM and ASF (the bad ASF).

As for the material used, I am planning to experiment with stuff and I have some in mind, but like I said, funds are tight so I'm trying to keep the guessing to a minimum

. HS5 gave a clue once to what it was, I looked it up and it is a common rubber type used in car tires. This got me thinking, do you guys thing it would be possible to use a properly sized fuel line or car hose of some kind? I am not sure if they come this small, but I believe you can get pretty close with some of these new fuel lines used in cars (I had to re-do the fuel system in my truck not too long ago). Fuel lines are also fairly rigid, which would reduce the "suck" effect pulling it into the barrel and would also allow it to press down evenly when hop is applied.

Just my 2c...

EDIT:
One of the reasons I chose to do this is because I have an SL9 and a G36c. Both have the same hop up unit so I can work with one and swap out of the setup I have in my SL9 to compare. The unit I will be keeping assembled is as follows:

- Bucking: Unmodified Guarder Hard, floss and teflon mod
- Barrel: Prommy 6.03 x 550mm stainless, polished with Brasso and waxed with quickwax.
- Nub: Stock nub.
- Hop up unit: Stock, unmodified.

For testing and for tuning the patches:
- BB: Bioval 0.3g unwashed.
- Distance: Test targets will be at 50', observations will be noted for further distances.
- Configuration: For the grouping tests all shots will be fired from the prone supported in 10 round groups.

- Accuracy: Prommy barrel configuration:
Testing set up:

Range:

Target 1:

Target2:

POA on the first target was directly at the bottom left corner of the paper. POA on the 2nd was center 10" from the bottom of the paper. Since this is about accuracy I am looking for grouping, not necessarily POI.

As you can tell from the POA on both targets, the BB is coming up into the target. At further ranges the BB continues to rise over the cross hairs and drops back into the cross hairs at 150 ft. (at 150 it's hitting head level, ~12" spread and I can hear it hitting the fence).

-------------------------------------

Put a few hours into this project yesterday, here is what I have so far:

These are the hoses I got. From Left to Right:
PVC: OD: 8.0mm ID: 5.04mm
Vacuum Hose #1: OD: 9.6mm ID: 4.0mm
Vacuum Hose #2: OD: 8.45mm ID: 4.2mm
Tygon RC Fuel Line: OD: 6.8mm ID: 4.1mm

The barrel that I chose to use was the stock barrel that was in my SL9 when I got it, that way I could swap it in and out with the 6.03 x 550mm Prommy that I have in there right now

Stock barrel: - (To be modified)
OD: 8.5mm ID: 6.03/6.04 x 509mm - Brass

You can't really tell from this picture, but I took this mostly to show how off center the bottom grove is from the hop up hole, however the index marks on the sides for the hop up clip are square with the stock hop up cut so with the inside of the bucking shaved down its not a problem.

This is the stock barrel cut:

Width: 3.8mm
Length: 4.1mm
End of barrel to cut: 1.57mm

After modified cut:
Width: 4.15mm
Length: 6.70mm
End of barrel to cut: 1.57mm

I only had time to get one mock patch made up before I lost daylight yesterday, but here is a picture with the Tygon patch installed:

Like I said, I will edit this later tonight to add a picture of the barrel cut that I made and the exact dimensions before and after. I was able to put a few rounds through it although it was dark, just to see how it was doing. This patch still needs tuning, but the over hop as is is promising. The Tygon gave much better results than I expected.

------------------------------------------------------------------------

Put some more time in today, tried a few new materials yesterday and made a few more patches, results weren't worth posting. The patches I got to fit had fliers everywhere at 50'. However there was something interesting. I tried out a barrel cut I have been thinking about for a while along with some other mods and some more outside the box materials and got a target like this:

The barrel used was complete trash, left over from an old project, originally from a KJW Mk1 extended barrel kit. Originally 600mm, cut down to 580mm, no crowning, no hop up cuts.

ID: 6.10mm
OD: 8.12mm
L: 580mm
Unpolished, lightly cleaned, POA Center

Long range was less than impressive. The BB flew straight and center all the way out and dropped to the ground around 145' with no hop adjusted on the arm. I am discounting the fliers and lack of range to the terrible state of the barrel, the 6.10mm ID and the 8.12mm OD compared to the 8.5 on most barrels caused the whole thing to be loose in the entire assembly. All in all I think this might be worth pursuing.

 

[bobgengeskahn]

My mistake, I'm not particularly active on the other forums, but I do spend quite a bit of time reading ASM.

I realize that the material HS5 uses is not a hose per se', but why couldn't you use a hose as a patch??? The key is the material characteristics of what he uses. He has not said exactly what it is or where he gets it, understandable since he sells the stuff in pre made sections so you can install them yourself. What I am getting at is the possibility of using something pre-formed to make your own patches. The one down side (IMO) to ASM is that a lot of people tend to over think things. HS5 himself said that you can do any of his mods by going to a hardware store and knowing what to look for.

And if by "Flat Hop" mod you mean the G-Hop, no. At the FPS I am currently running I don't feel like having to tear it down every game and re-build it. The G-Hop was developed in Japan for the <1J restrictions and is fine for that (although I have seen ONE person that has a G-Hop that is lasting after a few thousand rounds over 400fps). HS5 developed the R-Hop to give G-Hop like results in >450fps guns.

If you read my OP you would see that I have read both the ASM and ASF threads on the R-Hop, and I don't see why you are telling me to go back and read them since I initially said I was asking for clarification. I was hesitant to post something like this since the atmosphere here has been... dubious recently. Nothing against you, but if this is going to just turn into a "go to ______ and come back" kind of thread or "you don't have the skill to do this" kind of thread I'll just PM fuzzy and have it locked and people can PM me if they're interested to see how it turns out.

Edit:
From ASF:

Looks like it comes off of a hose or at least a cylinder and then hollowed out.

 

[bobgengeskahn]

@ Starfolder:
No worries, the boards recently have just been getting a little hostile over here and frankly its been putting me on edge about posting most of the time.

I don't claim to be some wonderboy when it comes to these things, I just like playing around, and theres no way to know if you can without trying

You're right when it comes to rigidity. HS5 emphasized on a few posts elsewhere that for the R-Hop to work its the angled cut in the front of the elongated hop up cut that keeps the patch from sucking in, not the rigidity of the patch.

Interesting work on the flattop, I hadn't seen that work before. Interesting to see the difference in the hop up cuts from manufacturers. It almost makes you wonder how much the manufacturers are holding back on us just for the sake of marketing :.

@Metallicfatcat:
I have read that too. I have done some other work on barrels with my dremel before, so I think it will be able to handle it. Worst case I have a hack saw, vices, files, 1000 grit sandpaper and all day.

One of our more well known members (vindicareassassin) was doing work with this (elongating hop up windows, custom nubbs etc) back when I first joined and we shared some PMs about the work he was doing that will come in handy with this as well. But from his experiments, he was saying that he was getting dramatic results by only elongating the window 3-6mm. I'll have to break out the calipers and see how much I can open it up on the G36 style unit since most of you guys like to play with the AR style units.

Since I have my G36c and the SL9, I'll try to do a side by side with my current ~550mm barrel and the stock ~509mm barrel that was in the SL9 before I installed the 550.

 

[bobgengeskahn]

@ Vindi:

The length of workable space in the G36 hop up has been my only concern in planning this. I won't know for sure how much space I'm going to have until I can get it apart and break out the calipers this weekend. But if its as small as you say it is then I have a few ideas that I want to try out. Since I have 2 or 3 spare barrels laying around I'll have a few chances to see how long I can go.

The only real variations I have in mind for the traditional R-Hop that HS5 invented would be a few small mods to the actual rubber, i.e the shape of it. I have a few other things I want to try in terms of buckings and whatnot, but those wont really effect the performance of what I'm looking at.

 

[bobgengeskahn]

I don't see why it wouldn't work since its just a patch... but I've never seen a cut on a M14 barrel. Although, I have heard that the M14 and the AUG have the same hop up unit, and I know my friends AUG barrel has the same cut as mine i.e. standard AEG cut.

Also, is there a design difference with the ER-hop? Or is it like the IR-Hop, just a different rubber for the pad? I have tried to look around and haven't found much of anything besides reference to it in other threads about the R-Hop.

 

[bobgengeskahn]

Vindi, correct me if I'm wrong.

I believe he is talking about his set up here:

Vindi:

I found some outer barrel extensions and am thinking that I am just going to use that with a suppressor to cover the inner barrel, plus itll give it a nice SD look

How did you stabilize the longer barrel in the fore-grip? I was thinking about getting a solid fore-grip and filling it with foam, but i love the look of the RIS grips

I rear wired my battery so I have a pouch on my stock but Im thinking about getting a LiPo and encasing the stock so it can still fold.

Yer tiz

You need to use M5 bolts cut to length, so that they hold the inner tight and the bolt head sits tight against either the forestock or in my case the RIS rail.

Do this both sides and it holds the barrel firmly, and the forestock steady enough to fit a bi-pod.

You can just make out the C shaped marks where the bolts press against the barrel outer.

Also notice tha massive chunck taken out to enable a large stick 9.6v battery to fit when its got one of those massive C length forestocks on.

Barrel spacers made from plastic card bent into U shapes and then fed over the barrel, the sides were left long so the glue had something to grab hold of, but not to long to interfer with battery fit.

Again notice massive chunck missing to enable big kahoonas battery to be fitted

Appologies for shitty pics, been relegated to using my phone camera and it aint the best, though it ought to be the amount I'm payin for it

" title="" border="0"/> ~I managed to put my camera through the washing machine not once, but twice, so its not just fekd, its proper fekd

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[bobgengeskahn]

For those interested, I modified the OP with an update instead of adding moster posts as I work along...

 

[bobgengeskahn]

Thanks AHP, in the heed of posting yesterday I forgot to add that information. OP has been edited to add the above information as well as various other stats on the hosing and modified barrel cut.

I have never actually done a grouping (for record) with my SL9, so that should be interesting to see as well. I figure 50ft. should be enough to see discrepancies in the patterns from either system, but if anyone wants to see from further or thinks I should set a further distance just let me know and I'll see what I can do. 120' is about as far as I can push though in my backyard, and even then it gets to be a stretch.

 

[bobgengeskahn]

Since the SL9 has the bi-pod built into the fore grip I am hoping that the effect will be like a floated barrel, and as long as I fire on semi the barrel movement should be consistent between shots, however the resulting down flex would give the barrel an LRB effect, but at least it would be consistent. The reason I hesitate to fire off of a sand bag is because of the resulting upfelx in the barrel would not be repeatable/consistent between shots...

Ideally I would be able to find a thin tube or sleeve that I could just slide on and off the inner barrel to shim it. I'll do some measurements this afternoon and keep an eye out for something....

 

[bobgengeskahn]

Bump for another update to the OP.

 

[bobgengeskahn]

Vindi, I have spent the last day or two theorizing on how I could do this, the most helpful article I have found (besides your post on ASM and a few of the PMs we have exchanged) is this article on classicairsoft.net http://classicairsoft.org/forum/content.php?127-LRB-Effect-using-an-AEG-barrel-bushings-set-screws

My question is: is it necessary to have the "step" in the barrel at the beginning of the LRB? I see that the poster in that thread preserved it with the set screw in the bolt, but is it necessary?

I like the idea of toying with this on my SL9, although I am not sure how I would do it quite yet.

 

[bobgengeskahn]

Thanks Woogie, I had a feeling that would be the case. If I do pursue this other barrel mod I will probably start another thread, or atleast retitle this one since it's nothing like the R-Hop. One other question, is the SHC hop-up (I think thats what its called) in the middle of the barrel on classics? I think that is what I have been seeing, and I have been contemplating it as a variance on this unit as well...

 

[bobgengeskahn]

I can't seem to find it right now, I'll see if I have better luck tonight looking around for it, but here are some other goodies that might be interesting to some people:
http://blackwaterse.hu/knowledge/kb_show.php?id=18

http://classicairsoft.org/forum/showthread.php?8918-KG9-Aug-Hop-AEG-barrel-collar-recoil-wt.-tuning

 

[bobgengeskahn]

Thats ok, saves me the trouble

 

[bobgengeskahn]

Alas, I think that I have decided to press on with something... unconventional. Nothing against this system or HS5 or anyone that wants to do this, more power to you. I have just decided to venture more into more unexplored territory... as far as I know... So instead of taking this thread off topic I started a new one for the build I am doing so that others may, hopefully be able to continue on with this if they so choose or find it interesting enough...

 

[bobgengeskahn]

From what I have read about it from various posts by HS5, the IR hop is a different rubber all together that is able to maintain its "sticky" or friction properties at a colder temperature. As opposed to the traditional R-Hop that, like most polymers, loses elasticity, and thus the "sticky" property as it gets colder.

For what its worth, the Tygon fuel line that I was playing with has the most promise, but the stock size of the line I was trying to use was too small, so it was a pain to try to get it shaped for the hop cut.