It is now reported the Las Vegas shooter used a dozen
bump stocked long arms. Like the so called Hellfire switch trigger puller at Waco - used to justify the death of
76 people or more than at Las Vegas so far - this is a relatively simple full auto if you will conversion. Not precisely selective fire nor an accurate designated marksman tool but can be mounted and removed.
For an example of a machine gun part that is readily available in the marketplace -All NFA rules apply to the sale of the SSF trigger - there are such things as
SUPER SELECT-FIRE SOPMOD (SSF®) TRIGGER
FULL DESCRIPTION
The Geissele Super Select-Fire (SSF®) Trigger is a select-fire combat trigger that Geissele Automatics developed for the U.S. Special Operations Community. The SSF is a non-adjustable combat style two-stage trigger that is available in 4.5lb. and 5.5lb. configurations. In semi-automatic mode, the SSF is a precision two-stage trigger that allows precise and accurate trigger control. In fully-automatic mode, the SSF is a single-stage trigger with a smooth, continuous trigger pull and abrupt hammer release. The SSF is safety certified by Crane Naval Surface Warfare Center. NSN# 1005-01-618-8104
All NFA rules apply to the sale of the SSF trigger.
First you have a full military version machine gun then you can add bells and whistles. This is not what the media is reporting.