Animation character has been reduced in size

Hello, I´m new in animations in Unity 3D.

I have used one animation (the "BaseMale" carácter downloaded from the asset Store) and I have done a firing animation using 3d Studio Max.
The animation is OK, and I have seen it very nice in the inspector of Unity.
The problema is that when I try to use it, Unity say to me that it can´t find this animation.

I have realized that if I put as a Legacy type then it Works, but Unity does a very strange thing, my character plays the animation, but it reduces its size about four times (it gets 4 times lower tan usual). When the animation finishes, he recovers his original size.

Any help would by appreciated.

I have tried with the scale parameter of the model (inside the animation), but it doesn´t work as I expected.

I am a bit lost, could you help me, please???

Thank You in advance.

German.