Here's my MPL-57. I built the mesh entirely from scratch. The texture is built by manipulating reference pictures of the MPL-57. Included are three variants: the standard MPL-57, the Homing Shot variant, and a version which has neither the scope nor the sight, so you can add your own attachments to it.
[spoiler]
(http://s23.photobucket.com/user/ggctuk/media/MPL57_Viewer01.jpg.html)
(http://s23.photobucket.com/user/ggctuk/media/MPL57_Viewer02.jpg.html)
(http://s23.photobucket.com/user/ggctuk/media/MPL57_Viewer03.jpg.html)[/spoiler]
DOWNLOAD (https://mega.nz/#!VJxy1ajI!1_GnSy2kcxz0sA8tttDqRkLWUR2DBe32LHn2mzJ0neM)
Credits:
-EA/DICE for the idea and the reference pictures.
You can modify this model if you wish, to add scopes, remove parts, or give it a HD texture.
EDIT: Updated with a higher-poly barrel mesh.