First off, I think you could probably do this with Logitech software macros, but a possible AHK solution is below.
Just copy and paste into an ahk file. One problem is that you can't right click to do anything else when this script is active, including turning it off. You'll need to kill the script from the task manager.
While you hold down RMB, it will spam "Q" every 1.25 seconds. Tweak that sleep # to fit your purposes. It'd probably be a bad idea to set it to a low number.
RButton::
while GetKeyState("RButton", "P") ; While the 1 key is being held down physically.
{
loop 1
{
Send {Q}
sleep 1250
}
}
return