I don't know. She's squatting so it might not be as big as you think. But if you want, you can give this the oversized_object tag.
Nah, look at her hand compared to the grip and trigger. Not to mention with the size of the rounds compared to the mag, you could fit upwards of forty-fifty rounds in it considering the E-Mag is double-stacked.
Still, props to the artist for putting the level of detail he/she did into this image. The rifle is beautiful, as is the red-head curled up around it.