SRC Metal One Piece Hopup Unit for MP5 / MOD5 Series Airsoft AEG

"this does not fit Echo 1 mp5.

the stabilization fins are in the wrong place,

its is very nice so it seemed like a waste to return it, i used parts from it to beef up the hop up already had.

"Purchased this hop up unit for one of my Echo 1 MP5's, but can not get it shimmed correctly to work. BB's will feed into the unit, but will not fire - perhaps a longer nozzle would fix the issue. Other than that it seems like a good unit.

Pros:
1. Adjustment feels very good, once you set this unit the hop up will not move on you.
2. Metal construction is very nice, this unit will last a long time.

Cons:
1. Does not fit Echo 1 MP5