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Madbull Airsoft Ultimate Hopup Unit for M4/M16 Series Airsoft AEG

14 Customer Reviews

by Christian B. on 06/12/2017
"If it helps a prospective buyer, I upgraded my Valken battle machine v2 with this hopup and it fit and functioned perfectly without any modifications to the receiver. So far it looks like a night and day difference from the stock one, I'm happy with this hopup!
by Robert V. on 04/04/2017
"I have owned this hop up unit for about a year and a half now and I've got to say it is by far one of the best hop up units I own. I own 2 prowin hop up units as well and I will say that functionality is just as good if not better than the prowin. This hop up can take a wide variety of buckings where as I know the prowin prefers thicker buckings. This hop up is very accurate and super easy to put together and install. I would highly recommend this hop up unit as a replacement for any stock unit that way one can get the best accuracy out of ones gun. The set up I use for my custom built p* jack is this hop up with a modify soft type bucking and an angel custom h-hop nub. I get very accurate and tight groups ~150 feet with .25s and my madbull 300mm 6.03.
by Debra L. on 03/31/2014
"This is buy far one of the best hopup chambers on the market. However it can be a pain to install. I have it and so do two of my friends. When i got it it took a lot of tries to get it in perfect because it has such tight tolerances but once i got it installed right it worked like a charm. However both of my friends had to file a few millimeters off the front of theirs to get it to work with out jamming. But after getting it working it will hit a man size target 3 out of 5 times at 70 yds laser measured with a stock M4. Over all i think this is the best hopup on the market and would highly recommend it.
by Catherine L. on 09/04/2013
"i really love this hop up actually and its really simple to assemble. well worth the money. but i have one big con with this product is the bucking it comes with. first off it barely even fits and if you even get it in perfectly the first time, consider yourself lucky. to solve this problem about a month later i ordered a REAPS hopup bucking and i was BLOWN AWAY with its performance in pair with this. i highly recommend getting the two

very well built
i love the wheel adjustment
easy to assemble
chamber lock

hopup bucking it comes with is too tight and bad performance
its a bit difficult to clear the hopup with the chamber lock thing

by Nicholas S. on 05/24/2013
"This Hop-up unit came with my madbull metal body and I am loving it. I purchased an Echo 1 troy which out of the box was claimed to have 400 fps. After my local indoor field chronoed it, it showed closer to 340 fps. so they put a m120 spring in to compensate. After pairing this hop-up with a new tight bore madbull barrel my fps sky rocketed to close to 450. I then bought a crawler barrel and replaced it to get closer to the 400 range required for indoor ranges. I plan on getting another unit for my tight bore for use out doors since it is so easy to switch out. Perfect alternative to a spring upgrade. Also my mag changes only cost me one bb so there is more shooting all around. however clearing it after each match can be a bit of a pain. Installation was easy and it came with instructions on putting it together which were a great help. Owned it for nearly 6 months and have had NO feeding issues. I easily run my mid-cap elite force mags and "made in china" mags that come with it. have yet to find a mag that wont run with this hop-up in m4 variants. Highly recommend this hop-up.
by Matthew B. on 01/29/2013
"Best Hop-Up you can buy period, end of story.

It feeds flawlessly at any FPS and retains BB's after removing the Magazine.

by Andrew C. on 12/23/2011
"I did a lot of research on hopups, most of the reviews for this thing were 5 out of 5, so I decided to try it out for myself. It came with very detailed directions and was easy to put together except for the bucking that came with it. The bucking that comes with it was too long so I had to cut about 1/8” off the front of the bucking to get it to fit properly. I didn’t have to make any mods to the gun to install the hopup. It takes a about a hundred or so BB’s to get it broken in. Once I got this dialed in, it worked perfectly. With the stock hopup and a madbull 120 spring, I was shooting at about 350 FPS, with the new madbull hopup it was shooting around 420 FPS +- about 3 FPS. It was very consistent and you could defiantly tell by the sound there was no air leaks. I have put about 7000 rounds through it so far without any jams or miss-feeds and have not had to make a single adjustment to it. If you have the money, I would defiantly recommend this and I’ll be buying another one for my next build.

Madbull Stag Arms metal body with a classic Army reinforced gearbox – fit perfectly without any mods

Airtight seal
Does not need to be adjusted once its broken in
Option to install the tracer unit
Solid construction
Easy to put together
dropped right in without any mods to the gun

Bucking needs to be cut down approx. 1/8”
It doesn’t always hold the bb’s after the mag is removed.
by Mathew U. on 12/19/2011
"Not the first hopup I've put together but the easiest!
1. The seal around the magazine is amazing - zero wobble.
2. upped my fps (same scenario as the last guy)
3. saves about a bb or two after the mag comes out
4. no exposed gears
1. assembly was easy HOWEVER only after i used a copious amount of silicon lube around the bucking
by Michael H. on 01/02/2010
"Recently I have fallen in love with Madbull and their accessories. My Classic Army M15 A4 Blowback was in need of a better hop up and decided to take the plung and buy it. I'm going to through the pros and cons then go into more depth.
1. Free Madbull 60 Degree Hop Up Bucking (Increase FPS).
2. Adjustment wheel stays solid and won't move when shooting.
3. Full Metal.
4. Comes with detailed instructions.
5. Flawless feeding.
6. Easier magazine fit.
1. Adjustment wheel is hard to adjust.
2. Takes awhile to assemble the hop up chamber.
3. If you shake the gun bb's fall out.
4. Not all bb's are saved when taking out the magazine.

1. The hop up bucking is a very good material just by feel. My gun shot 400 with .2's and standard inner barrel. I recently put in the 6.03 Madbull python II barrel and this hop up as well. The gun is now push 440.
2. My gun has blowback and because of that the normal M4 adjustment knobs move when I shoot for extended periods of time. I would have to take cover and adjust it every once in awhile. No need for that now!
3. Because the hop up is full metal it will work with a full metal outer body.
4. When I saw all the parts in the plastic bag I was overwhelmed, luckily they have text and pictures (THANK YOU)
5. With the added benefit of holding those spare bb's in the chamber I was worried about feeding. When I fired my gun though my fears flew away along with how fast my gun was shooting.
6. It may just be me but I my magazines fit easier and faster into my gun.
1.The wheel is hard to adjust but because it stays sturdy once you correctly "zero" it in there is no need to touch it again.
2. I am pretty familiar with M4/M16 hop ups and assembling this was like brain surgery. *To assemble this make sure you have silicon!* The silicon makes the spacer stick to the "stick" that puts the backspin on the bb. (Sorry do not know the correct term for it)
3. This most likely is not a con but thought I would mention. Unless you jump around when you change magazines this should not affect you at all. If they did not fall out there would most likely be a feeding problem.
4. Considering this device saves around 3 bb's I should not complain but thought I would mention it.

The pros obviously outweigh the cons with this. The cons hardly even matter in this case but thought I would mention them. All in all I am pleased that I bought this gem, not only did I get what I wanted but more entirely.

Hopefully this has helped you to make a valid decision on this miraculous item.
by zac m. on 02/02/2014
"i got this hop up a few weeks ago and have played with it at an all day event. first, those who are having issues, put any other bucking in it. it will make it a thousand times better. i just ordered myself a REAPS bucking because I've heard nothing but good things about them so i figured i would give them a shot. the only issue was that the adjustment on it is quite firm(which is actually a good thing i was just playing on a cold day so as the gun got inaccurate then i would get inside and it would warm up. anyway. i belive his would work in a scar, although it is about 1/4 inch shorter than my scar hop up. thanks al, and please write reviews so you can get a better idea on whats good and bad
by Steven M. on 01/16/2013
"Finally a review from my usage of it....This hop up unit is Amazing. Seals very tightly against the gearbox and the wheel Does Not Move!

Only con i can think of was that the blue bucking that Comes with it is a Very tight fit in the unit.....I'd use something else unless you want to use brute force to get your barrel out lol

No need to readjust wheel
Tight seal against gearbox

Bucking it comes with is almost too tight of a fit
by Levi C. on 09/12/2017
"Simply does not work in my gun. (Elite Force CQC). The other reviewers are exactly right about the quality control on this item. The metal this hop up is made from is not nice. It's rough and just not made well. It did not fit without serious modification. Even when I got it to fit I had constant feeding and jamming issues. I do not recommend this product. Maybe I got a bad unit but I decided to go with a Prometheus unit instead.
by Eric S. on 09/22/2015

Cheap look/feel
Metal is rough and unfinished
Horrible tolerancing will lead to problems

I got one of these with a Madbull Metal body. Seeing as I was going to buy the prowin hop up the next order I made I was happy to not have to anymore. Wrong. This hop up is so badly made that I had to sand it to fit into a body produced by the same company. The metal is just unfinished. you will have problems because it's not the correct dimensions out of the box. Unacceptable for an "ultimate" hop up chamber.
by Carlton A. on 01/07/2014
"The worst hop up ever.
It does not retain bbs, it lowered my fps by 250 (making my gun 90-100 fps), it does not shoot straight at all (BBS GO LITERALLY IN ALL DIRECTIONS), Double feeds (sometimes even shatters bbs) and the hop up bucking is awful.
Waste of money and I highly recommend the prowin hop up unit with a REAPS bucking over this.
This hop up was tested in a Stock VFC Mk18 Mod 1.

Rating: 0/5