Removing the M1 Garand tag for this and it's child posts, as though we know the Tea Party Militants carry them in BA, there's not enough of the weapon visible in the image to tell it's a Garand. As well, this image and some others seem to be a story like of Mika and Nagisa as First Years, which could be before the Militants adopted the Garand. If anything, the sliver that's visible looks more rounded, like a Lee-Enfield would be.

Which would also match with the weapon tag I'm adding to this and it's child posts, the Vickers Machine Gun.