I have the following problem: I want to insert a weapon in UE4 as a. FBX file but if I import the file in UE4 then the weapon is divided into very many small pieces! but how can I do that this is a weapon together?

Combine inside your 3D modeling application or choose the Combine Meshes Option on import. https://i.imgur.com/L1wlHlF.png

I have the following problem: I want to insert a weapon in UE4 as a. FBX file but if I import the file in UE4 then the weapon is divided into very many small pieces! but how can I do that this is a weapon together?
Thx

oh hey but when i reimport it as a skeletal mesh its all too smooth !
but thanks for your answer it helps me a lot !