Downsize A 3DS Model?

I have a model of a M9 that I downloaded for free. I imported the .3DS into my game but it is gigantic. I am very new to unity and do not know how to make it proportional to my character. I tried a negative scale and it flipped it upside down and bigger.

Thanks for anyone that can help a newbie like me.

No no no - you need to make its scale zero point something (e.g. 0.01 will make it 100 times smaller). Also remember to change scale on all axis.

Alternatively you can always use any 3D modelling software to make it smaller.