On the subject of Hudson and their own releases they have announced yet more alterations to their M3A1 grease gun GBB replica (BLK 2210HW) specification.
They say that they have improved the exteriour finish with a sand blasted matt look, and the build material is all now "heavy weight" ABS. They have also replaced several parts where reliability was an issue (they don’t specifiy which).
The blowback force/recoil is less in the new model which increases the overall durability of the model simply because the stress levels have been lowered (not exactly an improvement though), and the "buffer part" is now made from a zinc alloy to decrease wear and tear. Not quite sure what they mean by "buffer part", but 10:1 it is something in the recoil mechanism that kept snapping.