if it was a std v2/v3 then then easiest option would be something like the G&G ETU setup
NB: I said easiest but still a LOT of fucking about
Point being is the switch module uses a pos supply to 3 switches
TRIGGER, COL & SELECTOR PLATE
so it returns a positive signal from 3 switches to inform the mosfet what state of play is
In this scenario you would simply exntend the wiring from trigger microswitch up to front of gun
and if box stays put with selector etc...
then it will work with a remote trigger switch firing the gun
however the mosfet is shit so likely need replacing with Peru ETU
even though another £40 - it is all starting to add financially not just actual work involved
you could use other variants of fancy bollox internal mosfets
but the rather simplified ETU would be easier to extend than a more intricate all in one pcb mosfet
and the more modern optical units - well you'd need a far greater understanding of electonics
to extend or convert optical switches/sensors to ye olde anologue/mechanical switch for trigger
when my ETU shit the bed years ago - I did look at a crude system of latching transitors
to utilise the ETU in gearbox, but could not get a couple of basic transistors to switch/latch
& then unlatch as I needed to just use the ETU as a simple semi/auto setup
(you touch the trigger once quickly - it switches closed and latches until the cycle is complete
and the COL then pops and it unlatches and stops the power mosfet 3034 etc...)
yeah somehow the various states of the latching never quite worked out exactly as intended
no matter what I tried & threw together on a pcb breadboard = so fuck it I gave up
(and clever cunts Perun sorted out ETU options thank fuck)
but I went back to old school trigger in the fucked FFR A2 anyway
No matter what - this project you propose will no doubt have a fuck load of headaches to overcome
but something lke the wanky ETU setup is likely to be required with extended trigger microswitch
yeah I would think long and hard if the project is truly viable in the end