AAC AAP-01 Assassin Performance Hop-up unit
I´m disapointed by the fact, that this original part fit not perfectly in upper receiver, because of those two little screws in the side. Without them I´ ve got it in, but in following step it was not possible to fix this hop-up on the inner barrel, like by original black hop-up. So it stays loose, and I´m not sure, how long it wil be working. Another point - to change the hop-up setting, I have to demontage my Action Army AAP-01 Folding Stock everytime !!! This is no acceptable. Request return-ticket , to send it back to you. Thank you.