Does anyone know what this photoshoot was for?

Looks like it might have been for Machete.

…a nun with a gun. What else could it be besides Machete?

She’s about 13 years too late if she’s jumping on the Rage Against The Machine marketing campaign, Nuns With Guns

Hmmm…Hands filled with a customized Colt M-4 Carbine, with finger on the trigger and thumb outside the grip. Good thing that weapon is not loaded with live ammunition. That’s posing with a firearm, not handling one. It’s called “acting”…