Blender mesh and animation problems

I made a really basic gun with armature in Blender and it works just fine, but when I import it to Unity, the firing animation won’t work as expected
, instead of sliding only the top o the gun, it slides the gun itself front and backwards.
Here are some screenshots:


The mesh problem:
Thanks in advance!

How many bones do you have? If I’m not mistaken, you have only the one bone moving, right? If that is the only bone you have, then Unity(or maybe Blender upon export somehow) may be assigning all those other verts to that same bone, hence the whole gun moves. Make a root bone that doesn’t move, and assign the rest of the verts that shouldn’t move to it.

As far as the second problem in the last couple of images, I can’t tell for sure what it is. The typical cause of missing mesh parts are wrong normals.

I think the animation was working when I asked you, what I didnt see is that it was going too fast in unity. And the missing mesh thing I tried resolving the wrong normals, but nothing. I’m going to keep searching. Thanks for your help!