i keep finding myself doing it whenever im at school or just walking through the house. and for some reason i now have a habit of doing a bunker imitation when i go into my room...
anyway, just watch tv and walk the trigger for, well, ages. you be amazed how much faster you can get it going.
the trigger itself also affects ROF. ie the EGO trigger or the Samurai just take the piss when it comes to ease of getting a high ROF