Think its only available in 9mm and has had a long a troubled few years since its start and pretty sure it wont be any good to convert to rifle cals
Like a slide fire ** / Bump Fire stock (only any use on .22 Rimfire and shotgun in semi auto in uk) it interprets the word of the law exactly technically would still be legal if the action re chambered the next round but required an auto safety to be disengaged before pulling the trigger
Basically its a blowback with a last round hold open bolt every shot with the lever as the bolt release but placed for easy use
(** Fairly Certain nobody has brought in a slide fire and let it off where its been heard as tho legal would probably not be shortly after
)