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Madbull predates MAXX by ~14 years and one could say MAXX is a clone and an tweek of the Madbull.

It was the First Rotary Hop-Up for AR on the market.

If you unit isn't feeding...try replacing the hop-up packing/rubber/bucking.
 

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Madbull came first, tend to be hit or miss as far as I recall. Feed issues could indicate a variety of things - I'd work on figuring out why before spending $$ on it... Unless you just want something shiny and new, then get a Maxx or Retro Arms hopup with a Maple Leaf bucking:)
 

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Now that I think about it, I think Prowin may have predated Madbull now by a short amount of time...
 

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Think I first saw Prowin chambers 2012ish, was considered an improvement on the more expensive cast units from Madbull. Might have been around a little before then, just not locally / on my radar.

Would agree, current Maxx units borrow a lot from the old Madbull Ultimate 3 in 1 chamber which had BB retention, LED tracer integration, etc, back in 2010 :)
 

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I’ve found that fitting a new hop unit to your barrel, bucking, and nozzle can be a chore. Best to try and fix yours first.

Some people love Prowin. Some people hate them. I’ve had some issues with them feeding correctly, but you may be just fine getting one.

The one Maxx I own works fine. Nothing special. The BB retention is cool though.

I’ve been liking plain old, decent plastic hop ups, for the simple reason that they’re cheap and easy to modify if you want to. Nothing wrong with plastic hops in general, only with some specific ones.
 

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Discussion Starter · #9 ·
I believe the it’s not holding the compression anymore and hasn’t been for a bit

I have replaced the bucking 3 times. Ran the bucking in another hopup unit and works fine.

It’s the madbull ultimate 3-1. Idk what else to try and do to it

It’s going into a g&g gearbox
 

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Compression loss and feed issues that occured suddenly but isn't resolved by replacing the bucking... hmm. Nozzle still feel 'springy' when pushed into the gearbox? Nozzle reciprocating when gun is cycled? Hop chamber got good tension against the gearbox?

Could do the paper test to get a hint as to whats happening (invert gun with no mag, cut and place small piece of paper on top of BB feed tube and shoot gun in safe direction - if paper is blown off, indicates air leak due to issue with bucking, nozzle, or hop unit tension)

Also might try 'rocking' the hop chamber (pop open the ejection port and test fps / feeding while pulling the hop chamber rearward / towards gearbox with a finger. Can also try pushing bottom of the mag forward/away from grip or pulling towards it. If fps increase / feed issues resolved, nozzle length, hop unit tension, bucking lips are suspect)

Nozzle centering might be worth checking while you're at it (mag and battery out, shine flashlight into BB feed tube while looking down barrel - should dimly see nozzle ~centered in barrel)
 

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Discussion Starter · #11 ·
I have put another hopup unit from a different gun in and it works fine

I will try the paper test and see if that works

The gun feeds bbs into the bb slot but when you fire about 2-3 times it just rolls out of shoots about 2 feet. Adjusted the hopup. Replaced the bucking and nub.

But still has the same results
 

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That sounds more like some kind of jam is occurring. Verified the bucking mound is fully retracted in the barrel when the hop is set to zero? Barrel look clean? Might do the BB drop test to check for obstructions (pull hop chamber and barrel out of the gun, drop BB into the hop and see if it gets stuck in the barrel. It is normal for it to rest on the bucking lips, should only take a tiny bit of effort to push it past them)
 

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Discussion Starter · #13 ·
I did the leak test and the bb test

The first one did fine

But when I did the bb test it’s super hard to get through the lip part. I took everything apart and went to another bucking a nub and was the same. Took the original bucking and nub and placed it in another unit and was fine. Looked up a video and a lot of people say that’s the issue with them and takes quite a bit of modifications to change. What would be a good unit to change to

I use the g&g green bucking and a Prometheus barrel. Not against doing r-hop or any of those just not super knowledgeable about it
 

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I find that it's odd that this worked in the past and recently metal changes and a bb can't pass into the unit.

Can you take and post pictures of the hop-up unit from all sides and angles under good lighting?
 

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I did the leak test and the bb test

The first one did fine

But when I did the bb test it’s super hard to get through the lip part. I took everything apart and went to another bucking a nub and was the same. Took the original bucking and nub and placed it in another unit and was fine. Looked up a video and a lot of people say that’s the issue with them and takes quite a bit of modifications to change. What would be a good unit to change to

I use the g&g green bucking and a Prometheus barrel. Not against doing r-hop or any of those just not super knowledgeable about it

I had/have this exact issue with my MAXX hopup and a G&G cold resistant packing (it's the green one, if I had to guess the exact one you have). Turns out when I was reassembling the barrel and hop-up, I was pushing the barrel too far into the hop-up unit. As a result the rubber lip of the packing was being constricted and forced too a smaller diameter than the BB.

The solution, pull the barrel out of the hop-up unit by the absolutely tiniest of margins. I mean the barrel may not even look like it moved out of the hop-up unit at all and it may have solved the issue. Just keep pulling the barrel out of the hop-up unit by the tiniest of amounts until the BB will slip into the barrel with only a small amount of resistance.

FYI, if you pull the barrel out too far, you will suffer from nozzle to packing seal, and lose FPS. There's a fine line to walk.
 
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Also some hop and barrel combinations are more prone to this than others due to tolerance stacking. Might try resetting the barrel as mentioned above and leaving the C clip off, repeating the BB test to see if it's good before being 'clipped'. Rarely but occasionally I've modified the shoulders on a C clip so the barrel would sit a hair farther forward / not get pushed quite so far back. Want to be careful if you go this route, very small adjustments so the hop arm is still in the right place to apply hop.

Maple Leaf Macaron has about the loosest lips of any bucking I'm immediately aware of, if you happen to be able to pick one up locally it might be worth trying in a tight chamber.

R hop is better suited for heavy rounds btw (.30g or more), tends to over hop lighter BBs which makes dialing the hop in a pain.
 

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If not impossible...with .20g bbs for example.
 

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Discussion Starter · #18 ·
I find that it's odd that this worked in the past and recently metal changes and a bb can't pass into the unit.

Can you take and post pictures of the hop-up unit from all sides and angles under good lighting?
I was using an older bucking that had been used so it was softer but it ripped and had to replace it and have had issues since then.
 

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Discussion Starter · #19 · (Edited)
I had/have this exact issue with my MAXX hopup and a G&G cold resistant packing (it's the green one, if I had to guess the exact one you have). Turns out when I was reassembling the barrel and hop-up, I was pushing the barrel too far into the hop-up unit. As a result the rubber lip of the packing was being constricted and forced too a smaller diameter than the BB.

The solution, pull the barrel out of the hop-up unit by the absolutely tiniest of margins. I mean the barrel may not even look like it moved out of the hop-up unit at all and it may have solved the issue. Just keep pulling the barrel out of the hop-up unit by the tiniest of amounts until the BB will slip into the barrel with only a small amount of resistance.

FYI, if you pull the barrel out too far, you will suffer from nozzle to packing seal, and lose FPS. There's a fine line to walk.
I have the blue and the green but I will try this

Tried this out today and it worked. Thank you for the idea, wouldn’t of ever thought about that.

Thank you everyone else for all of the help
 

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Discussion Starter · #20 ·
Ok well it shoots now for about 2-3 rounds then I have one that goes about half the distance as they fly. Put the slightest hopup on and had the bb’s fly about 10 feet. But if I push the bucking back anymore it goes back to the issue where it won’t shoot and the bbs just roll out.
 
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