[dontask]

using a stock unported TM piston head will slow down the rof quite a bit

I found that my fully stock AUG increased in ROF when I upgraded it with a ported piston head and Guarder SP90 spring (lol I didn't expect that at all at the time)

edit: it might have also been because the O-ring on the new piston head didn't have as good of an air-seal