Springer instead of aeg ?
as been said - perfect shimming to make box run quieter
neoprene on fast/higher springs makes more slap so sorbo/neo mix is best
quiet pistons do work a little but use with silent cylinder head (Lonex is best)
Silencer/suppressor also knocks it down a bit further
different flash hiders make quite a difference
if anybody has a normal M4/M16 - place ya hand around the outer slots & DRY FIRE
(I said dry fire coz somebody is bound to shoot themselves in the hand with a bb)
just hold the flash hider in ya hand with slots mainly covered and you will hear a much louder crack
cheapy suppressor can be quieter but some are better than others
though an aeg will never be silent - hopefully a quieter duller thud with almost no schreech or loud whirrr of gears screaming