We want to share more information on how we design, build, and validate our products. Our lead engineer uses their product development experience to guide the design and deliver products that we can stand by. Our product lead uses their experience in the gun industry to guide our designs to be ergonomic and comfortable to use. We are so confident in our products that we use them on our own guns.
Materials
We use ASA and PA6-CF on our 3D printed products today. These are engineered materials that go above and beyond what products like PLA are capable of.
ASA is an alternative to ABS plastic. ASA has similar material properties to ABS with the addition of improved UV and weather resistance. ASA has good heat deflection, impact strength, and tensile strength. We use Polymaker ASA plastic, here is the datasheet. If we ever have material supply chain issues, our backup supplier is Overture, here is the datasheet.
PA6-CF is our high-performance material for larger caliber gun components. It’s an all-around better performing material than ASA. While Nylon is not typically UV resistant, PA6-CF has good UV stability due to the added carbon fiber. PA6-CF requires tight control of the print environment for the best results and an anneal step after the part is complete. We follow best practices to control our process for the best outcomes. We use Fiberon PA6-CF, here is the datasheet.
The table below shows a comparison of the material properties for each material that we use. A dash indicates that the material datasheet did not provide that measurement.
| Units | Polymaker ASA | Overture ASA | Fiberon PA6-CF (Dry) | |
| Young’s Modulus (X-Y) | MPa | 2,379 | 2,372 | 8,637 |
| Young’s Modulus (Z) | MPa | 1,965 | − | 3,760 |
| Tensile Strength (X-Y) | MPa | 44 | 45 | 109 |
| Tensile Strength (Z) | MPa | 32 | 33 | 54 |
| Bending Modulus (X-Y) | MPa | 3,206 | 3,221 | 7,038 |
| Bending Strength (X-Y) | MPa | 73 | 75 | 161 |
| Charpy Impact Strength (X-Y) notched | KJ/m2 | 10 | 13 | 11 |
| Charpy Impact Strength (X-Y) un-notched | KJ/m2 | − | − | 24 |
| Heat Deflection Temperature | °C | 100 | −* | 173 |
| UV Resistance | − | Excellent | Excellent | Good |
| Solvent Resistance | − | Poor | Poor | Excellent |
| Oil Resistance | − | Excellent | Excellent | Excellent |
*Overture ASA will have a very similar heat deflection temperature compared to Polymaker ASA. It’s just not listed on Overture’s datasheet.
Design for 3D printing
It’s important to understand the limitations of 3D printing and design parts accordingly. The strength of the interface between layers is limited by how well those layers bond to each other. It’s important to design parts to reduce the amount of tensile force transmitted through those layers. We design our parts accordingly, and if we can’t for any reason, we won’t sell it.
In the case of a magazine floor plate, there are two load cases that are the most concerning. First is when the magazine is fully loaded, and the internal spring is fully compressed. Second is when the magazine is dropped, and the floor plate impacts the ground. Those forces largely act perpendicular to the top and bottom, respectively, of the magazine shell. We design our floor plates so that the layers are at an angle relative to those forces.
Orienting the layers at an angle to the acting forces decreases the normal force acting on each layer and transfers more force to the plane of the layer which is the strongest direction for component printed using filament.
Validation
We test every part we design to ensure it will stand up to the forces exerted on it. We only list products on our website once we are confident in their design.
Range Testing
We take our products to the range and test them in various conditions.
Drop Testing
Concrete is hard, we repeatedly drop all our products on a non-coated concrete floor to test that the parts won’t break under the harshest conditions. We drop the magazines from a height of four feet.
Spike Testing
Our testing also includes spiking the magazines into the ground, although we don’t recommend doing that to any magazines, 3D printed or otherwise.
Fit and Contour
We do extensive fit checking to ensure the component fits snug and doesn’t interfere with the operation of the gun. This includes matching the interface profiles of all the components our parts interact with. We tweak the design until we are happy with how it assembles, how it feels in use, and how well it holds up to use. We typically go through several iterations until we are ready to list it on our website.
If our prototypes fail during testing, we will archive the project until we can find a way to design and/or manufacture it to our satisfaction.