Blank firing assault rifles and gunfight choreography

I am planning the choreography of a gunfight for a stage play and I am looking for two things: Advice on resources to consult to help with the choreography, and advice on places to acquire blank firing assault rifles for relatively cheap.

Always best to hire a pro for choreography, but J. Allen Suddeth has "Fight Directing for the Theatre" which isn't bad, and I published The Theatrical Firearms Handbook in 2014 that should be some help. As for cheap blank firing assault rifles, you're not going to find them. You can rent some from ISS or Weapons Specialists or there's a place in FL or NV too I think... but they're sure as heck not cheap. If you're on a budget and doing live theatre, probably best to use sound cues.

SAFD friend of mine recently shared a video of a blank firing AK she rented from Weapons of Choice - one of the revolver-in-a-housing deals. It vented straight down into the user's hand... probably okay if you're wearing long sleeves and heavy gloves, but for what she was trying to stage, they probably won't be able to use it.