>>64412522
Dunno, I havent examined the internals of my shotty trigger group that closely.
You can't just hold down the button or remove it, it needs to click on and then reset when it releases.
>maybe theoretically you could work out the exact bit that needs to be changed but you'd need to modify it correctly so it still does its job in a full firing cycle
Simpler would be to make like a bump-stock or recoil-absorbing stock where the receiver slides backward in the stock then at its rearward travel add on an artificial "thumb" that mechanically pushes the button at max recoil then it goes forward.
Or just learn to hold your own thumb at this point on the normal stock anyway.