Different look when importing same FBX mesh as skeletal and as static

I am trying to replace gun model from “FPS template” with my own model. I’ve placed my mesh on original gun’s mesh place using Maya and left all skeletal stuff unmodified. But when I’m trying to import result to UE4, it looks different from original if imported as skeletal mesh. Screenshots below demonstrates same FBX file, imported with and without skeletal checkbox:

What am I doing wrong?