- Great buy!!!
First off, being polycarb, this is very light and very sturdy. I installed this today and put about 100 rounds in a mini game. It's about 30-50% much more quieter. However the o-ring isn't the best so i inserted my kwa's stock one. That was too thick and it wouldn't stay, it just slid off in the cylinder; so i put the o-ring back on. I added extra grease to the cylinder and o-ring and it seemed to fix the entire problem. i chronoed it at about 420; (kwa m16 1st gen: about 410 fps stock piston head) so maybe it was the grease (probably not) or maybe (and more likely) its the o-ring, it may just seem loose, but it's airtight (just like on the package it said 100% airtight) and it probably is; hard to tell though.
Anyways, it's a great buy, much better than the guarder one that my friend has (heheheh) so yah, go ahead and push that 'add to cart' button... :)
ps: the grease i used was the madbull ones also available on this site.