The creator of the world's first 3D plastic handgun unveiled Wednesday his latest invention: a pre-programmed milling machine that enables anyone to easily make the core component of a semi-automatic rifle.

Within a matter of hours, libertarian Cody Wilson of Austin, Texas had collected more than 40 pre-orders for the computer-controlled Ghost Gunner, which his firm Defense Distributed is selling online for $1,199.

"I'd say it's a desktop machine that can mill aluminum," Wilson told AFP by email when asked to describe the black cube device in layman's terms.

"We've programmed it to easily mill guns for the uninitiated user."

The Ghost Gunner is certain to raise concern among gun control advocates who favor a ban on semi-automatic rifles in the wake of mass shootings such as the 2012 killing of 20 children in a Newtown, Connecticut school.

Wilson whipped up a furor last year with the Liberator, a single-shot, all-plastic handgun that anyone could make with a simple 3D printer, using plans released by Defense Distributed.

The US State Department forced Wilson to pull the blueprints off the Internet, citing the Arms Export Control Act, but not before copies appeared on offshore file-sharing websites.

The Ghost Gunner is programmed to mill the lower receiver of an AR-15 type rifle -- the key section that holds the weapon's moving parts, such as the trigger, firing pin and magazine.

A promotional video shows the plug-and-play device -- which ships with software and instructions -- carving a lower receiver out of a block of aluminum with a mechanical burr.

In the United States, where the Constitution guarantees the right "to keep and bear arms," receivers are the most regulated parts of a firearm, and typically bear a serial number.

The Ghost Gunner, however, opens the way for anyone to privately manufacture a lower receiver free of any identifying markings, then add a pre-manufactured stock and barrel to come up with a fully functional gun.

Wilson said the Ghost Gunner will be assembled in Austin, with deliveries to begin around Christmas. He expected to be able to take international orders "in the next two days."