Iraqis are permitted to own fully-automatic AK-47s in US-occupied Iraq. But the BATF won’t let you own an Akins Accelerator, a gizmo which attaches to the trigger mechanism of a Ruger 10/22 to achieve full-auto function.
Mr. Akins has posted in the Comments section, correcting my erroneous description of the Akins Accelerator. Mr. Akins says:
Nothing attaches to the trigger mechanism and it does not achieve full auto function because the trigger is functioned once for each and every shot. The entire barrel/receiver/trigger group reciprocates backwards under recoil removing the trigger completely from the finger and compressing a spring which then forces the barrel/receiver/trigger group back forward again.
Mr. Akins also provided a link to an illustration of what goes on.