magazine lip replacement for Beretta ASG M9 Gas Blow Back Full Metal airsoft gun

This is a lip for the magazine of Beretta ASG M9 Gas Blow Back airsoft gun.
Many thanks to member Huan He! ( http://www.thingiverse.com/chike_h/about ) who has shared his design ( http://www.thingiverse.com/thing:1165036 ) so I could better analyse how the mechanics of the magazine-lip works.

note! I have just updated the STL file to version 4. It contains a few small but needed changes. Now I feel happy with the result.

When you print it sand the bottom walls of the opening from inside where balls enter the lip from magazine so that balls can enter from the magazine smoothly.

Also sand with the file only the BACK wall of that opening if ball don't get through all the way up.

It should be enough of post processing.

Note: as the right bottom wall has a thin delicate appendix - be careful when post processing (cleaning from supports) as unintentional abrupt move can get it broken off.