by KYLE MIZOKAMI

In March, a Website dedicated to 3D-printing firearms announced one of its members had developed a lower receiver for a Colt CM901 rifle. It’s a small — but evolutionary — step toward the development of firearms that pretty much anyone can download off the Internet.

The CM901 is the bigger, badder brother of the ubiquitous AR-15. The CM901 has a similar design, but fires the heavier and more powerful 7.62-millimeter bullet, resulting in greater range and killing power.

A group of gunsmiths developed the CM901 lower receiver and uploaded an animated gif of a live-fire test. The clip is five seconds long.

3-D printed CM901 lower receiver in action. GIF via FOSSCAD

The CM901 is a modular design, so the rifle can shoot lighter 5.56-millimeter rounds, too. The group used a XYZ Da Vinci printer, which retails for around $500.

By the standards of 3D printers, that’s cheap.

Remember — this is an evolutionary development.

Downloadable blueprints for 3D-printed AR-15 lower receivers appeared on hobbyist forums several years ago. All you need is a 3D printer and enough thermoplastic, and you can build yourself one.

Cody Wilson of the gun rights organization Defense Distributed — which built the first fully 3D-printed pistol — developed an AR-15 lower receiver that can fire hundreds of rounds.

But it took a lot of trial and error, because the receiver’s components had to withstand recoil and the stresses from moving parts. Earlier version of Wilson’s AR-15 lower receiver broke after firing only a few bullets.

Rifles chambered for 7.62-millimeter are heavier — usually by about four pounds — and suffer from even more recoil than the AR-15.

It’s not clear if the 3D-printed lower for the CM901 will hold up after more than few seconds of rapid fire. All we see is a short clip.

“It has been tested, fired with little to no issues,” the group stated.