A guy at work mentioned that his MB01 had a restrictor valve fitted in the bolt assembly/chamber. I will have it apart tonight and have a look, if the bolt in the end of this is missing then maybe I can get something to restrict it without having to faff with a spring.
Found this on a thread on these forums:
- The gun actually has pretty good stock power, perhaps too powerful for the internals, with an FPS of 480 (without velocity reducer) and a poor 270 (with velocity reducer). Being the Version 3 of the Well, it has a removable velocity reducer (comes installed). To remove, you have to take off the cheek rest, remove the bolt and unscrew the reducer from the cylinder head. It's that simple. The way it works is by reducing the air flow, so even though you're at a lower FPS, the spring is still the same, so the strain on the internal is also the same.
Maybe I will get lucky and the velocity reducer is still in there.
http://www.airsoft-forums.co.uk/index.php/topic/5944-well-mb-01-l96-version-3-review/