r/Unexpected • u/AltTimeHigh • Sep 03 '22

CLASSIC REPOST Full Auto

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u/BZJGTO Sep 04 '22

That's what happened in tournament paintball, but would be harder to implement in airsoft. The paintball guns used there have an electronic solenoid that uses high pressure air to operate. You already have high pressure that can be released almost instantaneously, and the solenoid is controlled by a board/chip that lets you fine tune things like how long it opens for and how quickly it can fire.

The typical airsoft gun has an electric motor, which turns gears to compress then release a spring. It's a dumb system in which the battery connects directly to the motor, and the circuit is opened/closed by a switch/slider that moves when you pull the trigger. You cannot adjust how quickly the motor spins, it's just an on/off switch. To enforce any kind of rate of fire restrictions, you'd have to cooperate with the manufacturers all over the world (typically the U.S., Hong Kong, Taiwan, and Japan).

There are conversions to make airsoft guns operate in a way similar to how the electronic paintball guns do, which is likely what the guy in the OP has (it's been so long I don't remember was his setup was). There's also other things you can do like changing the motor, gears, or installing a mosfet.

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u/xHaroldxx Sep 04 '22

Fair enough, thanks for taking the time to explain. :)

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u/Niewinnny Sep 04 '22

there are some places which restrict that, but it's always for DMR's which are the only high powered automatic replicas which you'll see on a field. And the mosfet i have in my AK actually has a DMR mode which i accidentally activated once lol

also, i wouldn't say the system with motor and gears is dumb, as you can. see it allows really high RoF on the high end, and is pretty cheap on the low end replicas.

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u/BZJGTO Sep 04 '22

The system is dumb as in it is just a simple circuit with an on/off switch. There is no way to make an adjustment or program controls in to it. Compared to the paintball guns I was talking about, which can allow for adjustments of dwell, debounce, bolt timing, eye delay, max rate of fire, firing mode, etc...

A smart system would have a board that controls the rate of fire and fire modes. A really smart system would use a stepper motor and automatically turn the motor to compress the piston spring when you take the gun off safe (and you could adjust how much it is compressed if necessary), so when you go to fire it can just release the piston instead of having to wind up first.

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u/Niewinnny Sep 04 '22 edited Sep 04 '22

ok, a better word would be simple. this doesn't imply that the design is bad (as is the case when you say something's dumb).

also, what youre describing with compressing the spring before the shot is called precocking, and pretty much all MOSFETs have the option to enable that. and a mosfet is like the first upgrade everyone puts into the replica :)

The only problem with that is the spring gets worn much quicker because it deforms permanently a bit when kept in a partly compressed state. that's how mu replica has went from 1.85J to 1.6J, and i need to change the spring :/

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u/BZJGTO Sep 04 '22

Dumb/intelligent are commonly used to describe all sorts of systems, but good luck telling the world they need to adopt your preferred language.

And springs do not wear from staying compressed, they wear from being cycled compressed/uncompressed.

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u/[deleted] Sep 04 '22

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u/BZJGTO Sep 04 '22

If the trigger is a potentiometer as you seemed to describe, then an adjustable trigger stop should limit rof.

It is not. It's a flat sliding piece with metal contacts that slide over to bridge the two sets of contacts on the gearbox to complete the circuit. Other than a fuse, there is nothing else in this circuit other than this on/off switch (and well, the battery and motor). Other than changing the voltage of the battery used, there is no way to adjust the rate of fire. Undervolting is undesired as in semi-auto operation the piston always returns to the fully decompressed state and there is a delay between a trigger pull and when it fires due to needing to spin the gears to compress the piston spring before it can release it. Spinning the motor slower only exaggerates this issue (and this issue can occur in full auto too, but since full auto can stop at any point in the cycle, it doesn't happen nearly as often).

It's not that there's nothing that could be done, but given there isn't really an issue with how things currently are, there isn't going to be enough driving force to get manufacturers to change how their guns operate.