|| verified buyer
I have used a couple of these mechboxes for fixing a number of guns. I had a Marui G36K (custom) that had the stock mechbox fracture. I used this mechbox as a repair platform by swapping out all the upgrade parts from the old mechbox and putting them into the new one. This worked great.
I more recently used one to do a battlefield mechbox swap when my brother's Echo G36C had a piston break. The JG mechbox works just fine, and is inexpensive enough to have a spare on hand.
Great platform for upgrades
Actual FPS can vary a lot
Piston and piston head are cheap
The tappet plate can flex too much in high FPS situations
The selector plate is made from a brittle plastic that can easily break if the selector switch is abused