Hello all,
I've taken the time to read all the posts and I must say Bandit50 that in this case the latch being steel does offer a better resistance but that means that in case of you leaving your replica fall to the ground or like me trip in a branch and fall down on the ground with the replica under you, it may break on the upper receiver side and so much more difficult to fix.
I think is better that you have a part that you know is cheaper to replace. And I took the time to enhance the latch design to be more resistant.
I have yet again added the part to the Shapeways store. You can find it
here
in black and in white plastic versions. It's not dirty cheap but can be an alternative to someone that don't have access to a new stock or Airsoft stores nearby.