I'm pretty sure you can't, as shown by the media, because every weapon with with attachments or designed to look tactical is an assault rifle to them. Which also means a majority of people who have no experience or idea about firearms also have this same idea of what an assault rifle is. Just like if you point at an armored vehicle and say that is a tank, half the people are inclined to agree with you while the other half of people will tell you that it is just an truck with armor on it. Assault Rifle and tank are words that have been used to catch the attention and misdirect towards a certain goal such as ratings. Very few people are going to react if you said this gun is a semi-automatic sporting rifle, but if you say this gun is an Assault Rifle just the name is menacing.

I don't know your knowledge of firearms. But, based on the average media description of an assault rifle this rifle would be considered one.

https://en.wikipedia.org/wiki/Barrett_M98B#/media/File:Barrett_M98B.jpg

It has a butt-stock, it is black, and it has a detachable magazine, fires an intermediate cartridge. The only thing it doesn't have is a selective fire, but if you are the average person who knows nothing about guns you can be convinced that the fact that it has a selector safety/fire which would mean your description will be different from what everyone else is saying. In reality it is a bolt-action and can't even feed another round into the chamber without someone manually operating the bolt.

Another rifle for example: https://en.wikipedia.org/wiki/Barrett_M82#/media/File:M82A1_barrett.jpeg

This beauty has it all, a intermediate cartridge, selective fire (safe/fire), semi-automatic, and detachable magazine. The fact that someone can be convinced that this AMR (Anti-Material Rifle) is an assault rifle goes to show how shaky the actual perception of what an assault rifle is among most people.