Obscure as hell but it sounds legit. You have to excuse us for our caution, not only do we have concern about non legit activity but we are under the microscope by people outside shooting.
I know reenactors who have "live" guns but can only shoot them with blank charges so you would not be alone there. The comment that you used cartridges was what threw me but I guess forwards venting blank firer on ticket with good reason sounds not so bad.
Now lets look at the problem, you would do best to homeload blanks for the cartridge blank firer, the primer system is more reliable. That would be doable in a centerfire case.
“If a cricketer, for instance, suddenly decided to go into a school and batter a lot of people to death with a cricket bat, which he could do very easily, I mean, are you going to ban cricket bats?” :- Prince Philip said after Dunblane