glm::perspective takes fov as radians nowadays. So you probably want to use glm::radians(60.0f).

I just checked the glm docs. http://glm.g-truc.net/glm.pdf

It's not radians, its degrees.

Check better, that's probably outdated. See http://glm.g-truc.net/0.9.7/api/a00174.html#gac3613dcb6c6916465ad5b7ad5a786175