They are probably Airsoft rifles.
It's a competitive game/sport similar to paintballs, heralding from Japan. The rifles, although looking real, fire small plastic balls at regulated safe speeds.
(You could still lose an eye or a tooth, but skin contact is no worse than a bee sting).
Think Call of Duty video game meets paintball. It's pretty innocuous IMO.
(Assuming they are indeed Airsoft rifles)
Plenty of people do it in the UK, so if these photos were dug out of her social media accounts, it doesn't mean that much really.
I'd be more concerned about the publicly shared BDSM stuff myself.