That Age Old Question: How to Solve Semi Auto Lockups?

[Skara]

Here I am with another noob question.

How does one prevent a V2/V3 box from locking up WITHOUT resorting to a fancy mosfet with cycle detection?

It's an issue, but not really an issue to me as I am a full auto wanker anyway  But being able to have a consistent semi auto in my 933 and AK would be nice to have

I'm not going to slap titans or anything in those boxes, as they are wired for GATE external units (Warfet, Nanohard, Nanoasr, Nanotwat, etc.).

I know that a quick flip of the selector and a short burst temporarily fix the issue, but I'd like to avoid doing that.

Any suggestions?

 

[PopRocket123]

It won't completely solve them but it'll significantly reduce the chance of it happening. 13:1 gears and a high torque motor. The best motor would be the ASG CNC 30k motor. It'll give you around 25rps on a 7.4v lipo and near instant trigger response. It'll be nearly impossible to lock the gearbox up on semi. 

 

[Skara]

It won't completely solve them but it'll significantly reduce the chance of it happening. 13:1 gears and a high torque motor. The best motor would be the ASG CNC 30k motor. It'll give you around 25rps on a 7.4v lipo and near instant trigger response. It'll be nearly impossible to lock the gearbox up on semi. 

My 933 already has 13:1s and a nice SHS HT motor (29k on a 7.4), it still locks up though.

The AK is an E&L and has a torquey af (stock) motor with standard 18:1s.

Both guns have AB turned on so the cycle is consistent.

 

[Asomodai]

I had massive problems with lockup on Gate PICO AAB style mosfets. Not sure if its the same for the other models. Even if you were pulling the trigger at reasonable speeds on semi it would still lockup far too many times. Switched them out for Perun no AB and haven't had a problem since. A number of people pointed out I must have been pulling the trigger too fast or not fully enough, however other people have come out the woodwork and reported the same problem.

However before I realised it was that, I just drilled a small hole in the side of the receiver where the cut off lever is so I can jam an Allen key in to go full auto. It was a real pain to unlock DMRs otherwise.

 

[Steveocee]

PDiK ?

(yeah yeah I know not helpful but it would solve the problem of lockups in semi)

 

[Chev Chelios]

Was messing around with those Systema High Torq motors when they first come out on a V2 gearbox mechanically locked to semi with a mechanical switch. Took the AR latch out and even at 400 FPS the spring could not move the motor even when half cocked. It ran happily for years. Not sure it is something I would recommend but it never locked up.

 

[Adolf Hamster]

Both guns have AB turned on so the cycle is consistent.

Well there's your problem

Seems counterintuitive but for the v3 box at least ab alone (without precocking) has a nasty habit of causing lockups by stopping too soon.

Try turning ab off/ using a nanoasr and that should help.

 

[Sitting Duck]

I'd need a bit more info tbh to understand it correctly...

So excuse a ramble on this shit about what I sometimes do...

As been mentioned AB can be an issue if it brakes & stops on a tanner as they say

(leaving COL just slightly raised)

Personally I don't use or have AB (except in the m904g)

Lockup's can often occur releasing the trigger too early (get gun running at say 18rps+ helps avoid this)

People think they MUST have AB - ergh no you don't

ensure COL is in good condition, replace with steel one if fucked

(see if it sticks to motor = steel/ferrous or crappy stock alloy which will wear more over time)

On a gun that will likely spam on semi a lot - I tend to use a steel COL

next I carefully - VERY CAREFULLY file down with a smoothed curved tip the trigger tip that activates the trolley

**** NB - I HAVE SPARE TRIGGERS SO I CAN AFFORD THIS RISKY MOD ****

The idea is to have JUST enough of the trigger's tab pushing the trolley but will pop ASAP

(rather than 2mm tab popping later)

The risk is on a full trigger pull to its limit it will jump off the trolley at full pull

so then you try to limit the final pull by adding material/screw or what have you to hand

in v2's the force required to pop the trolley is much greater than on v3's I've found

especially at full pull, where the v2 trolley is rammed up to the hilt so the COL is fighting to raise the trolley & pop

so if you can limit the final travel point - there will be a bit of room in front of trolley to allow some "give" to pop more easily

(the v2 trolley works but it has it flaws like at full travel, plus the trolley return posts can break on old v2 boxes

yeah the v2 box has a number of qwirks or flaws to say the least imho)

When you are testing a v2 & v3 trolley popping by rolling sector or gears whilst pulling the trigger

the v2 requires more force than the v3 I've found - plus the trolley return stop is a thick part of casing

so unlikely it will break like old v2 posts

also be careful if popping the v2 COL manually by hand with thin screwdriver...

if you pop the v2 by hand yourself & pop it too high, the trolley may jump up so high, when it returns it gets gets stuck

all crooked & wedged against the post, failing to drop/settle back into level position

(then you gotta open the box up to correct the wedged v2 trolley - so test by rolling sector/gears)

The above & more is a bit of a wank to mess around with, unless you are a tart with OCD like me

I don't fuck about with manual hairline triggers anymore as such, but look to reduce pull & take up slack instead

Test trigger from safe/rest & how much play you can feel before it engages trolley...

I don't add material so much now, but have a few "speed triggers" = shitty flat triggers with a bit of slack

& they often at full pull start to jump off the trolley....

(so nowt to lose as they say)

I bend the trolley tab - couple of light taps with hammer or manually bend tab in vice/molegrips

so there is virtually no play - you need a smidge of play to allow trolley to settle after popping & reset properly

but fuck the days of adding bits of material and hoping the epoxy holds on trigger tab & even trolley - fuck that crap

so just take up the slack from safe/rest point - hardly any play in trigger/trolley

(if you go too nuts - bend back slightly and/or file it down a whisker)

filing - ensure the trolley tab is not too sharp, slightly smooth/round the edges that the trolley edge can glide off

rather than a sharp edge holding the trolley

try to set the trolley limit - reinforced gearboxes have a trolley limit tab often in top half of box

here add a small bit of material (hard plastic/alloy epoxy onto the tang of trigger)

so now the trolley pull is lessened at full pull to avoid stiffness when popping

or prevent trolley jumping off trigger tab at full extended pull

So after all that crap, the trigger pull is reduced (at final limit)

there is nigh on no slack before trolley moves

you can also partially straighten the copper prongs, so they are less flared

(thin nose pliers can do this without stripping down the switch into its components)

leave a slight tiny flare, just reduce flaring of contacts so switch engages sooner

fuck adding bits of solder & shit to trolley contact - slightly straighten the contacts will work quite well

test trolley makes contact & slips inside the straighter prongs, hopefully very little of trigger tab is pushing trolley

so that as soon as COL lifts it pops ASAP, but due to the nature of no AB there will be some slight over-spin/cycle

BUT not as bad as before as the COL/Trolley is popping asap just as the piston is released

and pops JUST the motor begins to lurch to full speed with no load any more

and the chronic overspin is greatly reduced and less variation I have found in where the piston parks pre-cocked

The trolley pops asap, the box overspins/pre-cocks less

(still will overspin/precock more on 11.1v than on 7.4v - duuhhh)

BUT no way as much overspin as previously on std stock stuff and/or with worn COL etc...

A bit of fucking about, but not really as much as the tedious hairline trigger project

with a lot less gluing & filing than on hairline project

YES - there is some risk - but most of it is on just the trigger itself

& I'm sure most have a spare trigger or two lying around to play with

coz that really is all you are going to modify, by bending that tab, filing it down a smidge

ensuring it is smoothed & just a millimetre or so pushing the bottom of the trolley foward so it pops asap as the COL rises

(but ensuring you limit the trolley's final travel point somehow if there is a stop tab in box

or add material to case/rear of trigger on case where it pivots etc....)

So you get a "reduced trigger pull" that pops asap, reducing overspin etc... etc... without need for AB imho in snappy builds

(PS - add a tiny tiny smear of grease ffs to trolley & trigger tab to ensure it glides smoothly off when it pops)

Problem is due to TM compatibility BS & high quality precise Chinese engineering to fine tolerances (sarcasm)

these components are made to be very forgiving at times, meaning there are a lot more play/slack tolerance

so that you get a lot of trigger play at times before trolley engages and when the cheap alloy COL wears

it struggles to pop trolley (failing sometimes when really worn), which has a little more quickly at full pull

(where the COL was fighting more to pop trolley rammed home into switch)

So it all pops much much later and overspins more as the motor speed ramps up on release of piston etc....

Try popping a v2 - using the sector rotating by hand at full pull & feel the resistance

then try a v3 - much less resistance, this extra resistance will increase wear on alloy COL's imho

so if you reduce trigger travel, lower the height of tab engaging trolley (risky), take up some slack etc...

The whole operation will function more precisely (if lucky & done correctly with a few hand tests)

popping as early as possible, less resistance/wear & much less overspin & even less wild variation where piston stops

Then you won't need AB in quite a few cases/builds using the old school trigger/trolley setup

so you won't get it stopping dead with a risk of lockups & increase heat from AB that you probably no longer really need

reduce trigger pull if possible, less tab height pushing the trolley forward = it all pops asap

so less overspin & no real need for very strong AB or even no AB in most builds

lockup from auto to semi - well shit can happen sometimes

unless you use a fancy mosfet that ensures cycle is complete on auto

but a tiny bit of time taking up some slack, reducing the lift required to pop trolley etc...

will reduce overspin & need for many cases of strong AB imho

with the motor you are using it should enough grunt to fire no matter if it is 99% precocked

(unless the motor/wire is a bit crap)

so think your lockup is down to very strong aggressive AB, leaving the COL slightly raised (dead zone) on semi

a bit of trigger tuning & you won't need aggressive AB in most builds I reckon

 

[Sitting Duck]

Additional bit....

thought you was referring to M4's/v2's

for reg v3's the main component is this bit..

the silver part, file down the point a little from the back at a slightly different angle

& round/smooth it at the edge - test in gun

v3's you can lift the COL yourself with fine screwdriver as the trolley doesn't risk sticking like on v2's

if jacked up too high - you'll understand why there is a guide/rail on the v2 COL arm to guide the trolley back

without jumping too high & wedging itself at the trolley post

Anyway - v3 trolleys pop with less resistance than v2's I've found,

can test by activating the COL with screwdriver

but best test is rolling the gears/sector and get it to pop

JUST as the COL starts to rise and you feel the slight resistance & POP whilst the COL continues to rise

At that point - you have tweaked/tuned the trigger to trolley to pop as early as possible

which will reduce overspin on a non-AB gun - it will overspin a little bit (bit more on 11.1v)

but nowhere like crazy or double firing (if COL in good condition etc....)

weird thing that the v3 trigger/trolley/shuttle seems to move forward and slightly downwards as engages the contacts

so less likely to jump off at full max pull like the v2 can/does if left unchecked or not limited somehow

you can lessen the pull length by epoxy some material like 1mm plastic

(old sim/credit cards tend to 0.7mm thick)

between the black & silver components - just below the silver pivot axle lugs dooberry

(or just on one side only where the lug that sticks through top half of gearbox safety mechanism

anyway - the old school v2/v3 triggers, see if you can CAREFULLY reduce the height of trigger tab that activates trolley

so that the trolley pops up asap just as piston is release before motor ramps right up

it is a faff I'll agree & has some risks, so ONLY attempt if you have some spare bits or try it on a shitty spare box first

It does work to reduce overspin on non AB snappy builds

(and depending how nutz you go fine tuning it all, improve trigger travel/response a bit)

but fuck trying the hairline shit on an old school trigger switch - to get it anywhere near a real hairline is a lot of agro

and imho is never going to be like an ultra fine hairline ETU setup (and certainly not binary speedsoft crap either)

get gun running at 20rps or more - no more releasing trigger too early risk

turn off AB bollox, fine tune trigger to trolley to reduce any overspin

(that is what I tend to do - if I can be bothered or want to take a little bit of time, but sod hairline crap)

in very rare cases some sectors have the COL cam set later than usual - like 1 tooth later

so with those odd reject or piss poorly made sectors you will get more overspin

but only found one gear with cam 1 tooth out/later

if you look carefully - the one on the right will release the piston a tooth earlier at least

allowing the motor to spin up to full speed before the cam approaches the COL to pop trolley

(much more overspin)

View attachment 64965

(but this is a rare example, but if your sector is a bit retarded then yes you will get more overspin)

biggy pic to see more closely...

 

[Steveocee]

I dread the day I have a problem and @Sitting Duck answers it.

Man you are so awesome and your descriptions and answers are literally perfect but dude, you make the guy who wrote the bible look like he wrote a post it note lol

 

[Skara]

Cheers Duck,

I'll see what I can do!

Trigger response isn't that important in these 2 guns to be fair, I mostly play outdoors and use full auto a lot (like a real wanker), but sometimes the target is just too close (say within 7/8 metres) to burst his ass, so having a reliable semi auto would be nice, I already have one super wanker gun for cqb and another one is in the works (as soon as King Arms is kind enough to restock in Europe -.-)

I reckon I could disable AB on both and give the ak a slight hint of precocking (specna 933 overspins like a motherfucker anyway so the piston always stops at mid travel from the SHS HT + 13:1 inertia, while the AK still runs on the standard E&L torque motor and 18:1s).

I'll give it a try tonight when I get home and see what happens.

 

[Sitting Duck]

On the Specna 933 with 13:1 etc...

is why SS comes in handy to slow over spin when shit runs a bit too quick

On full length guns like 455mm AK's you gotta have full stroke or just SS 1 tooth only imho

(to get the volume for longer barrel)

So longer AK's you can't go too ultra nutz as you will get overspin on full stroke m90 spring

and going really nutz will just be tempting PME on a 1j AK

but on say 300mm barrels SS helps avoid PME, slightly improve response a little

& slightly reduce overspin a smidge too with heavier spring (compensating for shorter stroke)

volume permitting of course hence SS 3 teeth on a 300mm gun is quite common with a m110/115 spring

then usually you should get a snappy 25rps with little pre-cock, no double firing etc...

(maybe 20rps on a 1j AK or just a smidge more if tweaking the trigger/trolley perhaps)

bit of pre-cock is fine if running 11.1v, just park it for storage a half full 7.4v at end of day

BUT we know all of this anyway - just at times some shit does work & apply to other builds when pushing things

and if certain shit helps then we often tend to consider incorporating some weird stuff into other/next gun(s)

if it is wank or doesn't seem to help much or does fuck all then we bin that idea & move on

 

[Skara]

On full length guns like 455mm AK's you gotta have full stroke or just SS 1 tooth only imho

(to get the volume for longer barrel)

It's a 74u, so the barrel is 220mm or so  I can definitely SS the thing but I'll do it once the stock piston dies.

I could SS the specna too, but it only runs on 7.4s because at 30ish RPS bbs start to become expensive

 

[Sitting Duck]

It's a 74u, so the barrel is 220mm or so  I can definitely SS the thing but I'll do it once the stock piston dies.

I could SS the specna too, but it only runs on 7.4s because at 30ish RPS bbs start to become expensive

Well 3 teeth SS equates to a 10mm spacer inside the piston (almost) on spring power

3 x 3mm teeth = 9mm less stroke vs 10mm spring spacer, near enough same spring tension

Take a hot 395fps gun, remove alloy spacer about 8.5mm

(m3 bolt & nylon lock nut on a full/partmetal rack piston)

No spacer & SS 3 teeth is like 6 teeth removed - each being "roughly" M05 or 16.4fps

(6 x 16.4 = 98.4fps lost, from hot gun = 300fps now)

improve seals & new/strectched piston o-ring on shitty hot cm.517 = 330fps final power

pop in a snappy motor, mosfet if required and go nutz on the cheap 

but yeah wait until it breaks is good advice, just saying 1 tooth = 16.4fps or M05

and spacers can boost spring power if left a bit low afterwards

(or if spring chopped too much & up shit creek for boosting power)

NB: rough calculations but a pretty decent rule of thumb imho of what to expect when SS-ing

 

[Adolf Hamster]

one of these days someone is gonna have to sift through duck's backlog of posts and stitch together the true complete guide on how to gearbox

 

[Skara]

one of these days someone is gonna have to sift through duck's backlog of posts and stitch together the true complete guide on how to gearbox

I mean, we're all on lockdown so we have plenty of spare time

 

[Adolf Hamster]

I mean, we're all on lockdown so we have plenty of spare time

not sure even lockdown grants that much time

 

[Sitting Duck]

Cheeky bastids ???

Anyway most of it all is about 95% repeating what I

& others have already said

It is all about little things we all try & use

and we all do stuff slightly differently

Learning what works/what doesn't for US in OUR GUNS

Like the sorbo, AoE, PTFE,

LiFe/LiPo/Niamh/Titan Lithium Ion

What MOSFET & do you need one

What is best gear/motor

blah blah blah

In the end we are trying make our shitty toy guns a little bit better

(hopefully - but it doesn't always go to plan)

 

[Adolf Hamster]

Cheeky bastids ???

you know its true though

tbf it's good to get this stuff out and said, a lot of the little details can often be missed.

like filing down the trigger i've only done once to make a mis-matched mp5 trigger and trolley compatible, never thought to do it on other guns.

 

[Sitting Duck]

you know its true though

tbf it's good to get this stuff out and said, a lot of the little details can often be missed.

like filing down the trigger i've only done once to make a mis-matched mp5 trigger and trolley compatible, never thought to do it on other guns.

cheers sir, but please chaps practice this on an old box/trigger

It is NOT something I recommend EVERYBODY do on EVERY box !!!

As stated it is for sad bastids with OCD etc...

Trying to obtain imidiate tripping of COL asap etc...

To reduce overspin on snappy non-AB guns

Grab an old box, fuck about a bit with it

learn to understand how the trigger, trolley COL etc...

How it all REALLY works first, how it trips and resets

How the trolley slips under/over the COL

(it is a tiny bit more visible on a V3 imho)

Don't waste too much time attempting a hairline trigger

but gain a little understanding of it all in operation

Then you will see how you can improve upon how it functions

and fine tune it to operate smoothly & pop reliably asap

If nothing else smooth the tab a little and grease the trolley/tab

to at least assist in the trolley disengaging from trigger

(A dry sharp tab will only wear base of trolley over time)

Plus if you can somehow limit the pull slightly,

(so the trigger isn't ramming the trolley fully home)

which will also promote wear & leave less room to pop

(especially on v2's at full max pull, not good ramming trolley to max)

Sometimes when you change the COL, the new steel one

may not reset/return fully coz it just catches on the trolley guide

(Right at the tip of the "ramp" that it slips under to pop)

So a slight file to eliminate any snagging etc...

Even a minor smoothing to ensure the trolley slips under/over

during its operation in both modes etc...

(if required btw, but you decide all this

once you got a better understanding of it all etc...)

Other shit like ensuring selector plate has no burrs

glides silky smooth back n forth to lift the COL etc...

(could go on about checks to AK linkage system,

But this post is quite sad & long enough as it is ?)

I'm sure there are many many weird saddo stuff

we might do in our pursuit of improvement

I won't list all them coz you will REALLY think I'm weird

(well more weirder than you previously thought)

Have a mess around with an old box...

get a better understanding of it all

and the whole area of trigger, COL, trolley, switch, selector etc

will operate more smoothly & reliably with a smooth light pop etc..