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Custom Hopup's

4443 Views 38 Replies 6 Participants Last post by  bobgengeskahn
Well figured I would beat BOB to the punch......

Lets hear all of our LRB design options, or anything else that you may have.....
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Well, in that case I guess I'll do a cross post with some added details and a pic...

This is what I was playing with last weekend:

Don't judge the dremmel work too harsh, I was doing this on a whim...

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

It's a work in progress, but I think it shows some promise...
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Yes it is! I figured that was the effect that the H-Nub and the SCS go for, so I tried combining it with some principles from the R-Hop and that's what I got. It still needs a lot of work, but this was a proof of concept since I've never seen a barrel with this kind of cut.

Edit: now that I am looking at the picture, I can see why it was pulling left... the cut I made on the left (pic. right) is slightly longer... I think with a mill, or very patient hands, somehting like this would very easily shoot straight and true without any modification/adjustment after installation...
I didn't really go into it with ny expectations, more curiosity. The thought came to me through observation. The general design of the expensive "top end" nubs out there are trying to get the buckings to engage the BB at about 10 and 2. The problem is that there is no support in the middle, so you end up with a hard contact at 10 and 2 and this soft spot in the middle. Now, the other direction DIY is generally going is long and soft contact, for lack of a simpler explanation. So what I was going for was minimal surface contact and long exposure at controlled points on the BB.

I am pleased with how it turned out, definite room for improvement, good proof of concept for how crude it came out. I already have ideas of how I would like to build a unit around it with a system that would be very reliable, no real moving parts that would effect the BB itself and would be able to actually adjust to negative hop. ;)

It might actually pull me away from pursuing the R-hop
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I have thought about different ideas along those lines. I like the tune-ability idea, but recently I have been going a different direction, so it would actually counteract the idea of prolonged exposure... unless I'm missing something.

If you cut out the top and make it one hole... you'd have an R-Hop or ER-Hop...

Not sure what you're referring to with shimming the hop up... I didn't reference anything... I think, but maybe I missed something...

Here is an analogy of how I am looking at this problem... in principle, not really application. Think about bowling:
Waxed lane
Varying weight balls
"proper" technique

I won't elaborate on the "proper" technique for bowling, but typically there is s spin, be it back or lateral spin that people will use to get the ball to where they want it to go.

With this in mind, a traditional/modern hop up would be like cutting your throw short, releasing at the hip, and flicking your wrist to put a dramatic spin in the ball as it goes down the lane. For some people this works. However, if you watch professionals their movement is fluid and almost slow, they have a long release and a lazy rotation on the ball as it goes down the lane. This is almost the effect that I am looking for in the BB with this hop up.

To paraphrase what I said in my last post: long, consistent, gradual exposure to the hop up is the goal.

But enough about my stuff, I'd really like to see what other people are doing....
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woogie said:
That is an awesome way to think of it bob..... but when it comes to the bowling balls, they have a central core that will help the ball rotate in a determined direction. More weight on one side will cause the ball to hook or slice more. But in theory you have it about right.
In the same way BBs have different densities and air pockets. My thinking is that having a longer exposure on the bucking allows the BB to "find a CG"... somewhat based off of HS5s "vibrations" theory that he talks about on ASM.

And I remember those nerf guns. Applying that to airsoft seems complicated, i.e. lots of moving parts. But if you can think of a way to apply the principles I think it would be interesting to see.
If you have any old hard drives laying around they have a lot of small powerful motors in them, and they'd work off a lot less than a 9v. You could probably rig a resistor on a control board and run off of the main battery too.
That's what it sounds like. I actually had the idea to model a hop up cut after this not too long ago after seeing an episode of mythbusters:

I never played football, so I had never seen one before, but if you notice one of the wheels is canted so it actually does give the ball a spin as if someone were throwing it.

For our application it would be different, but follow the same principle. My thinking was that you could have one or even two stationary spiraled or diagonal "buckings", and since the BB is moving, maybe this would create a similar effect? I don't know. I decided not to try it just because of lack of tools money and time since I am trying to pursue this other idea, but I think it would be really interesting if someone was able to try it out.
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So... would you not plan to use any air to push the BB?
So Vindi and I have been exchanging a few PMs about a build I am doing, (I am actually going to start a thread on it right after I post this) and we figured that some of the information would be good to have here as well since it talks about hop up and some of the LRB characteristics that people are starting to take an interest in. The background is basically that I am going to try and put a modified LRB into my SL9, if you want more specifics you can check out the other thread that I'll post after this, but here's the convo. My original questions are in white, Vindis' replies are in yellow.

Hey Vindi,

So what I have planned is to build a refined version of my twin hop and combine that with a LRB style set up in my SL9. The way I am planning to do this is to remove the stock outer barrel set up and replace it with a 1"x1.5" aluminum block that I will fit and modify in many ways to fit these aforementioned modifications.

I did think about modifying the stock barrel mount system by cutting, shortening and drilling out the front a nd rear sections, and removing part of the centre section that would get in the way, and then manufacture a deflection system that would pull the barrel into an upward curve in the middle, rather than either pushing up or bending the front down.
I was only discouraged from such a project due to the fact of only having 1 barrel cradle available, so if I f**ked it up I end up with a totally broken gun and there was a much simpler system to try the LRB out on IE the EBR chassis ;) ;)

However I have 2 questions that I think you might be able to help me with before I start cutting on this... after I can find some bar stock with the right dimensions.
1. What is the "normal" amount of movement or off-set in an LRB barrel?

When you say 'off-set' I take it you mean deflection or bend, 'off-set' when you talk about LRBs is a separate thing, it actually refers to the amount of 'step' the bb has to jump in a 'normal' LRB to produce spin, as your aware in my case, and probably yours, a TM style system is used, but mostly to hold the bb in place and give that little extra 'flick' to rise the bb.
As for a 'normal' amount of bend or deflection, it realy all depends on everything else with in the system..... barrel length, barrel material, amount of previously induced spin, bb weight, bb surface, fps, etc, etc..... this is why its so important to make the barrel bend adjustable so you can adjust the bend to balance along side all the other chosen parameters

2. What has your experience been with different barrel materials? This hadn't occur ed to me until you mentioned it in the hop up thread.

I have a SS barrel in my SL9 now that has enough length to cut and modify it for this project, but I am hesitant because if I mess up I wont have anything to revert back to.
I have a madbull teflon coated barrel in my ASR, not long enough for this project, but I have liked the performance in that applications. However, with this system I am not sure how it would do, in addition I am not sure how the teflon coating will react to a Dremel.

In my experience rougher is better. SS is not good, its just to slippy to drag the bb.

I've got a 509mm madbull teflon in the EBR as we speak as I was trying length over grip, again way to slippery and requires way more bend to be dialed in than should really be necessary. Like you I too was a tad sceptical about cutting a teflon barrel but I did however extend the hop window with my dremel and the coating seamed to stay in place ;)
Vindi! I'm jealous, you've actually made progress
I've been a little held up this week and going into next.

I love the Aug mod though, I know a few people that would be interested in this. 2 questions though.

1. I am assuming you still used a shaved bucking, tied and teflon taped?
2. What method did you use to cut the barrel? For my build I am thinking about ways to do it with a drill press, but due to the nature of the cut I'll be trying to make I'm not sure how to do it cleanly.
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A mitre saw!? Impressive! I think for mine I'll have to set up a jig for my dremel... that is if I didn't mess it up too badly trying to use it as a router the other day...
Ooooooh... I think I missed something initially... I was wondering about the extended barrel cut... although those pipe cutters work great for shortening the barrel... and making o-ring groves ;)
Ah, thats probably one of the most useful dremel attachments, especially with the EZ Lock. I actually just got a diamond disc for cutting and this guy

Diamond disc is amazing, high speed cutter, not so much... I think the next thing to get will be some grinding bits...
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