"Other contemporary sources describe it as innovative, but how it differs from traditional Long or Short stroke piston systems already in existence at the time is unclear.

Jane's Infantry Weapons hypothesizes that it replicates the system from the previous Serial Bullet Rifle/Serial Flechette Rifle in which 3 chambers were cycled in and out of alignment with the barrel to give a rapid 3 round burst.

They base this on the design being well regarded at the time but being held back by problems with the contemporary flechette cartridge that later development solved for the ACR.

[1] As with the Steyr ACR, the sabots left the barrel at high speed, this was noted as presenting a potential danger to other soldiers, as well as to the shooter if they bounced off the ground when firing prone.

The choice of material solved AAI's issues with previous flechette rifles such as those developed during the SPIW program.