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Subdeacon Joe

3D Powder????

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https://3dprintingindustry.com/news/scientists-3d-print-gunpowder-substitute-achieve-420m-s-bullet-velocity-173623/

 

Researchers from the Xi’an Modern Chemistry Research Institute in China have 3D printed a functional gun propellant using SLA technology. The gunpowder-esque substance is a carefully constructed blend of photopolymer resin, RDX (a high explosive), and other reactive additives. Initial gun testing of the 3D printed propellant has garnered some promising results, as the scientists managed to achieve a more-than-lethal muzzle velocity of 420m/s. This, of course, depends on your definition of ‘promising’.

Printing and testing the gun propellant. Image via XMCRI. Printing and testing the gun propellant. Image via XMCRI.

High-velocity projectiles

Gun propellants are the chief energy source in barrel weapons, and are the driving force behind the high-velocity projectiles commonly known as bullets. In the black powder muskets of old, bullets typically exited the barrel with a muzzle velocity of up to 370m/s. In modern rifles, this number can exceed 1200m/s, but anything above around 70m/s can penetrate human skin.

Currently, the main ways to improve the ballistic efficiency and damage potential of propellants are to increase the burning surface or the burning rate. This is commonly done by foaming the propellants, coating them, or packing them in their casings in selective layers. According to the researchers, simply filling the cylindrical casing with a granular propellant works but is quite limited in its energy release efficiency. So, the team looked to 3D printing to see if it could pack a greater punch.

3D printing gun propellant

The first step of the experiment involved formulating the propellant, which consisted of three main ingredients. Photosensitive epoxy acrylate was chosen as the core material matrix, as this demonstrated an excellent balance between curability and viscosity. Next up was the explosive filler, and the researchers opted for fine RDX powder with a mean grain diameter of 25 microns. Finally, Bu-NENA was employed as the energetic plasticizer, which increased the whole energy content of the propellant without increasing its viscosity.

Preliminary compressive loading test with the propellant. Photos via XMCRI. Preliminary compressive loading test with the propellant. Photos via XMCRI.

Once the UV safety of the newly formulated explosive was confirmed, the team 3D printed a set of thin disks, each about 40mm in diameter. These disks could be stacked on top of each other to form a longer cylinder, resembling the body of a bullet casing. Each layer featured a honeycomb-like structure with holes and was about 5mm thick.

Then came time for the grand finale – the gun test. The cylindrical stack was loaded into a 30mm barrel with a 200g mass acting as the bullet, although at 200g it’s probably closer to a mini cannonball. The team set up a high speed camera and an internal pressure gauge in the barrel before pulling the trigger. Once the smoke cleared, the researchers calculated a rather high pressure exponent value of 1.46 and a muzzle velocity of 420m/s, with plans to increase the chamber pressure in future tests.

 

That's just short of 1400 fps.

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Interesting sure, but why would you ever do it?  It's gotta be faster and simpler to make powder than to print some disks. 

 

Reckon ballistol will clean up the residue? 

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It’s all good till your printer explodes. :lol:

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2 hours ago, Ramblin Gambler said:

Interesting sure, but why would you ever do it?  It's gotta be faster and simpler to make powder than to print some disks. 

3D printers can already print various metals, in addition to plastics.

 

Once complete assemblies can be printed, then any caliber, any load, with any bullet can be manufactured on demand "lights-out" with no tooling changes. Even print the tray in the printed box in the printed case. Print the shipping label too.

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2 hours ago, John Kloehr said:

3D printers can already print various metals, in addition to plastics.

 

Once complete assemblies can be printed, then any caliber, any load, with any bullet can be manufactured on demand "lights-out" with no tooling changes. Even print the tray in the printed box in the printed case. Print the shipping label too.

That I did not know. I can’t imagine the metal would be of a high quality.

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2 hours ago, Utah Bob #35998 said:

That I did not know. I can’t imagine the metal would be of a high quality.

Aircraft parts too:

 

 

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I'm all for new research. While this exact setup may never see production, portions of the research may make it to new products.

 

I wonder if they researched caseless ammunition in their journeys?

 

 

caseless_ammo.jpg

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