I'm supprised that no one has invented a different low pressure formulation that burns with the same characteristics as gunpowder/smokeless powder (as appropriate).
Would remove the need for the blanks crimp and therefore massively reduce debris risk, seems like a no brainer!
They kinda have.
Fiocci do 8mm blanks that are used in BF-replicas of 9mm weapons. The blanks are about as long as an empty 9mm casing and have the open end curved over to hold a bright green plastic cap, similar to a shotgun shell.
What is required in the UK is that blank-only pistols are visually distinct, e.g. a different colour. But that's purely an aesthetic thing because accurate replica pistols are also de facto illegal here.
With the exceptions of things like theatrical, TV, film and re-enactment use, as specified in the VCRA...
A firearms manufacturer could produce a small number of blank-only versions of their guns for sale to film and TV companies. They could look identical from the outside, which is what would matter in the context of film and TV.
Easily done, especially with something that has a removable barrel. Really all you'd need is a solid barrel with a small hole for venting at the front. You'd need either sufficient resistance to cycle the action on blow-back type models, or appropriately modified gas parts to cycle the recoil versions.
There's a bit more to it, but it's perfectly viable for the majority of auto-loading weapons and even easier for those that aren't.
More likely, though, manufacturers themselves wouldn't be interested in just a few small quantities of modified weapons in what is more of a mass production set-up.
It's far easier for specialist armourers to make aftermarket modifications to suit. However, there may then be the issue over advertising revenue and product placement sponsorship deals, as there'd be no direct incentive for a manufacturer to sponsor a film, or for the film to choose specific weapons.
It's big money, sometimes, which will have an influence.
