Great hop up unit. Installed in a stock CA M15A4 2009 X-Series. The previous hop up unit was shot and I when I went to investigate what was causing the problem, I broke the flimsy c-clip for locking the barrel onto the hop up unit, so I decided to get this upgrade.
Full metal construction makes this a durable, long lasting, and reliable hop up unit. Range improved dramatically over the stock hop up unit (by a factor of 2). Range comparison was performed using an all stock gearbox/barrel with a Systema Bucking and an Echo 1 H-Nub.
The c-clip, though also plastic, was made much thicker and tougher and won't break as easily as the stock c-clip. It fits very securely over the barrel notches and is actually semi-difficult to lock into place due to its tight fit.
As mentioned by previous reviews, the nub arm retention spring is indeed a bit too large to properly fit into the unit (both diameter and length wise). The easy solution was to take your existing spring from your stock hop up and voila.
- Metal Construction.
- Increases Range.
- More Reliable and Consistent over Stock Hop Up.
- C-Clip is Durable.
- Nub spring is too large to fit into unit without modification.
Rating: [5 of 5 Stars!]