Wells M4 gearbox limitations

I have 2 wells with metal boxes (I know). One CQB and one MRT. My CQB has been pretty reliable and one of my favourite toys. I have it sitting at around 275 fps which I like to think os pretty good with the short barrel and ported cylinder. Put an M95 spring in it and it sorta just stayed where it is.

The MRT was a dead stock inheritance from my old man and I messed around with the air seal, o ring etc and I can only get it to around the same fps.

Wondering if anyone can point me in the right direction as to how much more spring I can put in to get to that magical 300 number.

An M90 spring is going to give you around 270-280FPS, so an M100 spring should get it up to 300FPS and shouldn’t overtax your gearbox.

That said, I’ve built plenty of V2 gearboxes that chrono well over 310FPS with an M90 spring, so it should be acheivable… it’s all in the integrity of the airseal.

Sometimes you have to think a little outside the box by adding a small o ring to the inside of the t piece, repositioning the nozzle rubber or the t piece itself, etc. to tighten up the setup.

It depends on how much work you are willing to put in for minor gains and risk of gearbox casing failure , or how much you want to spend to do what you want out of a fancy CNC box or other gearbox conversion.

Without any work, an m90 spring should get you 300fps, if it doesn’t use a bearing spring retainer and it will, usually that gets it a little over. The gearbox casing will fail and crack the front off in standard form after an unknown time. I have seen some do it standard form in the warranty period, and I have seen some last a couple years! Most though, maybe 6 months of regular outdoor play.

The issues with the standard metal box:
poor seal between cylinder and cylinder head
oring loses its seal after a bit of use
the hinged door pistol grip does not lend itself to good pinion to bevel alignment.
the motor tower has movement that also leads to poor pinion to bevel alignment.
factory shimming is… factory shimming.

I also, have a cqb and mrt.
My cqb has seen over 6 games outdoors with drum mag and no love running m100; with no cracks yet doing a comfortable 300fps.
The parts and work done to it though…

  • Radiused gearbox. All eight corners of the cylinder opening. Spread the impact forces on the front of the gearbox over a greater area rather than focus them in a sharp corner.
  • Added a rubber washer glued between cylinder head and stock cylinder head pad. Not so much for “AOE” but more for absorbing some of the impact force on the front of the gearbox.
  • SHS piston with nylon SHS head, piston head ports bored out to 2.5mm. This was lighter than the piston assembly, has a good seal, and the nylon piston head is a bit less impact force into the front of the gearbox.
  • 3d printed a spacer around the tpiece to fill the area between the gearbox front face and barrel adaptor, this is a bit of an experiment but I have used it on a blaster that the front was completely blown off, held on only by the tappet plate, and the blaster works as normal. I can not say if it prevents breaking the gearbox but it definitely will keep it running for a bit longer after it breaks. So far I am convinced it helps prevent it breaking, I have a few mates and random people testing this for me.
    *Cylinder head sealed better to the cylinder. Using a couple wraps of gas fitting tape UNDER the cylinder head o-ring, then really tightly fitting the cylinder. The standard blue cylinder is gone for a stainless one, but that is more a personal preference. After a bit of use the standard blue cylinder will be shifting with the piston, it just isnt tight enough and will lose some airseal here.

The above is more about prevention, I doubt it is a cure though. The following is more for the performance I wanted

  • 13:1 gears short stroked 4 teeth
  • M100 spring with bearing spring retainer.
  • Lower speed high torque motor, with a good bearing tower that has no movement on the shaft, with 13:1 gears it has similar rate or fire as standard.
  • Replaced pistol grip with one that aligns the motor properly and doesn’t have a hinge door. A major issue with them standard is the pinion is not located solidly, and the shimming is shit. so they nearly all come back with a stuffed bevel and pinion. Replace the pistol grip and motor tower, good shimming with proper bevel to pinion alignment gets rid of that issue.

So far, it has worked, and performs slightly better than standard. I have gone up a spring and it now does 330fps, however yet to test at a game though has dumped a few drums in the garage and no sign of cracking yet. It has also been using with double drums by my wife who has no concern if it breaks, and I have told her to break it. She honestly is hammering it, and it seems to be surviving with no cracking yet, so far so good!

The MRT I got only a few weeks ago, It is setup the same but with a full stoke, 18:1 gears and a 45k ASG Infinity motor. Full cylinder, M100, bearing spring retainer, and the barrel is a 350mm 7.4mm i.d. Testing many mags in the garage and a load of dry firing it does a nasty 27rps and 370fps, which will likely drop to around 350fps once the new spring settles.
I will likely drop a tooth off the sector gear and trim the barrel down to about 310mm, just to pull a little power out of it to make it more field legal. However I am going to run it and see how it goes.

I am trying to break them, and trying to prevent them breaking for as long as possible. So far all this works well, the tpiece spacer is definitely the secret sauce though. I have a mate who has been running a cqb with one, and it was cracked almost completely on one side when I put it in over a year ago. It might be broken now and only held together by the spacer, normally without that it absolutely would be. He tells me is it still works fine so I can’t get it back on my bench to verify anything! That’s good right?

Anyway… I have fixed hundred of metal wells gearbox blasters, and it is always sad to see the gearbox broken, but even more when it is earlier than people hope and deserve. So I have always tried to do a few things to help it last longer. The catch is to do everything I have done to mine is a fair amount of parts and labour, so generally not worth it when you can just get a better blaster and be happy. If you own it already and can do your own work it is okay. They are decent performers as they come, and easy to work on so that helps, it is hard to not recommend just spending the extra on a more reliable blaster though.

Sorry for the monster post, I even tried to keep it short, but there is so much information worth sharing.

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I have changed out the pistol grips more for comfort than anything to the hg007 ones. My CQB stripped a pinion and bevel gear after a few games and I assumed it was the motor height adjuster backing itself out. The hg007 seems a lot tighter with the o-rings.

The monster post is great. Heaps to digest there. If they break they’ll get fixed. They were cheap enough and I like them.

Drilling out the piston head is an interesting one because I changed one to the shs nylon head and noticed the holes were alot smaller so i may try that next time its apart.

I like the hg007 grip, comfortable and good motor position and hold.
Yes just start with the smallest drill bit you can and move up 0.5mm at a time, I have done them out to 3.5mm, but honestly noticed no benifits beyond 2.5mm.

Ok for anyone following at home.
Messed around with the air seal on the long one. Grew some fresh gels to a slightly larger size.
Fps came up to around the 290 mark.

Ordered a couple of m100 springs off aliexpress and i think they sent me the wrong ones or they are extremely counterfeit

Wong sproing , sum booody put wong ordah thru :rofl: :+1: Thanks China

I always order 10 packs of m100 springs from Aliexpress, they used to come in the blue SHS box and were everything the same as the blue SHS box springs. Then last time a got a bunch they came in the clear plastic box, similar to the x-force springs. And with a long barrel, good seal and gels would get close to 400fps… fear not as they tend to settle to about a typical m100 power after a few weeks and a bit of use, if you got them from the same seller anyway. Bit annoying if you are itching to use it somewhere with fps limits though.

These came in a red packet. Looked legit. Might save them for something without a porcelain gearbox housing though.

Usually red packet SHS springs are a bit hotter to start with, then settle to their m rating and last a long time.

Here is the only wells’s I own. Both cost me fuck all, and have been the grounds for testing the limits of the gearbox and my work. Many of the parts also were dirt cheap from clearance, sales, and left over from other builds.

The cqb has lasted 7-8 games at mango and Donny. Always used with the double drum.
13:1 short 4 teeth
Frankentorque motor (neo can with the wells motor armature). Has about same rof as normal wells but nicer semi auto.
M100 with bearing spring retainer, SHS piston and nylon piston head, standard cylinder head with a 2mm rubber “aoe” pad.
Radiused, and 3d printed tpiece shroud to jam between front of gearbox and barrel adaptor.
Hits average or 305fps, shoots straight and so far no cracking. It’s next outing will run an m110, as I wasn’t to really test it.

The mrt is yet to be run at a game but has had loads of mags in the garage.
18:1 SHS gears full stroke, SHS piston, aztech piston head. Red wells cylinder head with an aoe pad… bearing spring retainer, radius, tpiece shroud. Also has a 45k asg infinity motor thanks to ausgels recent sale. Custom wiring too with SHS trigger block as I didn’t have the wiring loom.
Also used a metal well v3 outer barrel as the stock one had the tip flopping around and wouldn’t sit straight.
It hits about 27rps on 11v, and 330fps.
I have also kept the stock trash hingey grip, just to be stubborn and test wear with a decent motor that doesn’t have tower movement, though I suspect it will still have a poor angle and wear prematurely.

The disclaimer is I am trying to break them, but also trying to make them last.
The tpiece shroud I designed and printed has made wells gearboxes with the front totally broken off work. So even if it fractures catastrophically it will work until the upper receiver is removed so that’s a fun side effect.

Currently injured it could be a while till I get a chance to finish thrashing them to their doom.

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Anything you prefer the M type springs over the AG 1.18? Just curious is all. I found the AG to be not as harsh on the box.

Yes ausgel springs are not as harsh, and normally I would recommend the 1.18 for a wells box. In my case I am doing what normally breaks it, and seeing if/when it fails. I am still convinced that their gearboxes are an alloy of aluminium, magnesium and flour. :laughing:

I have know people to run m100 springs in them but only lasted a few games.
I know the cqb has had an m100 for 6, maybe 7 games and isn’t cracked yet however it is short 4 teeth and only getting m90 full stroke power levels. Which is roughly equal to the ausgel 1.18, but far harsher on the front of the box.

Again, the cqb has been bumped to an m110 (it’s an asg m135, but they are actually an m110 as their ratings are pure wank). So now it hits 330fps.
Again, I’m going to break it, but I need data on what does it and how long.

Most of this comes down to the tpiece shroud, if the box breaks it can’t go anywhere, and can still run, but will it prevent it breaking? Even better would be if it can stop it getting worse if it is already cracked. That’s what I am testing.

Cool got it, destruction testing :laughing: Like it.

I still have 2 I think BNIWrap of the dreaded Well grey cast complete boxes I bought from M4A1 back in the day collecting dust on the parts shelf I was waiting for the CQB and MRT to blow up. The CQB won’t die as of yet that has done a hell of a lot of ball ejecting and the MRT doesn’t get used much. Replaced the cylinder head to alloy, 1.18 , o ring, bearing retainer, when seals are good they are reliable 320fps.

Why I was impressed with a $99 blaster that a lot of people had issues with yet mine still soldiers on. With a few simple upgrades thrown at it I think they are great.

I must have a Wednesday built one and everyone else got Monday and Friday slop jobs :laughing:

I’ve been inside sooo many of them. And some just last, even when abused and neglected. Others, fail in the warranty period. I think the biggest problem is most of them fail sooner than people would like, and given there are so many out and so many versions it is law of averages too. Heaps out there, heaps of failures.

You don’t here about the ones that are years old and just soldiering on. Which is kind of the story with my tpiece shroud thingy. I have never seen one come back with a broken casing, likely as even if broken they still work as the front is held in place. People don’t bring me things that are working, unless they want upgrades, which generally if the wells is working as intended with a slightly bigger spring, they are alright.

If you get one with the gears reasonably shimmed and the motor height set right, and the motor tower is one of the few with minimal movement, it will get for a good while. Usually I would see them with stripped gears and mushroomed pinions in warranty.

You must have jagged a winner :slight_smile:

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There are heaps of them out there. I remember when M4a1 was in my state and they had a sale the lineup out the front and down the street was like going to see Taylor Swift. I couldn’t believe it. Then they sold out at 10:30am 1000 of them :rofl: I bet quite a lot of those are in landfill now as things changed.

Shame, because I always liked the Well CQB as a blaster… good looking unit, and one of the better sliding stock setups around.

I had one a few years ago, didn’t give me any grief… sold it to a girl down on the GC to use competitively, friend of a friend… but I never received any progress reports on how long it lasted in gameplay. :man_shrugging:

The nylon body version’s cheap enough to consider as a viable option for a gearbox swap though… even a $35 orange CYMA box is going to give you a more reliable unit that lasts over the cast alloy Well box.

Then again, you could always just buy a $99 CYMA Warhawk and screw a $70 Noveske short handguard on it. :+1:

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Always wondered why people prefer cast alloy to a good nylon box. There are so many opportunities for poor metallurgy with a cast box as thin as those required for AEG. Nylon is capable of absorbing more vibration and shock, with the only limitations being side loading on bearings. Agree that low cost CYMA orange boxes are more effective solution. Trigger/fire select is the only thing that usually acts up

Gotta love the shorties and I agree they looked and felt way cooler than a JM at the time. Plus charging handle to play with and the dust cover. They did pretty well. Proprietary mags but meh they were cheap reliable and the drum mags too. Still got og of both mags and never give trouble. Never had to pull apart.