Columns inside of a Container

I put columns inside of a container and noticed the container was just a bit smaller. Will this affect the text, images and so on. Like to know before I get too far along. Any other suggestions, perhaps a Div and set it to the width I need?
Thank you in advance

For my sites, I usually prefer using a div to create my own custom container or content wrapper that way I will have complete control for each visual break point.

Thank you @matthewpmunger