Q & A

Great question, also one without a direct answer. Why? Because the settings you use depend on the part you are slicing, the filament, and the printer you are using. It’s also not that complicated. Copying someone else’s settings may appear easy, but won’t teach you anything, and when you need to slice a new part, or trouble shoot an issue, you will struggle.

I like to start with the slicers default profile for the printer I am using. Tweak that until you get a good 3DBenchy. Don’t worry about printing a strong part, work on print quality first. After that, adjust your wall count, infill type and density, line width, and layer height to get the part to the needed strength.

This is a bit over simplified, but it outlines the basic process. Focus on print quality, and then on printing strong firearm parts. While you can jump right into doing lower receivers and frames, I think it better to print smaller items to get things dialed in first.

Check out the page on slicer settings for more details.

Nozzle temps and bed temps depend on the filament you are using, your printer, and even the type of part you are thinking.

I normally set the nozzle temp in the middle or higher end of the manufactures recommended temp. Higher temps are not always better.

Your bed temp should also follow the manufactures recommendations to start with. Different plastics respond to bed temp differently, don’t assume that a higher bed temp will reduce warping.

Slumping is another problem to consider. Too high of a bed temp can soften the part near the bed and cause it to slump. This can be a big issue with PLA.

Tough question. We use a number of different filaments. There are always pro’s and con’s. Check out our page dedicated to filaments under the “Learn” menu.

Nozzle temps and bed temps depend on the filament you are using, your printer, and even the type of part you are thinking.

I normally set the nozzle temp in the middle or higher end of the manufactures recommended temp. Higher temps are not always better.

Your bed temp should also follow the manufactures recommendations to start with. Different plastics respond to bed temp differently, don’t assume that a higher bed temp will reduce warping.

Slumping is another problem to consider. Too high of a bed temp can soften the part near the bed and cause it to slump. This can be a big issue with PLA.

ABS and ASA have similar mechanical properties, though ASA is more stable and generally better. I do not use these plastics when printing firearms parts because of there poor mechanical properties. The tensile strength tends to be low, and layer adhesion can be very poor without a heated chamber. ABS / ASA does have the advantage of good heat resistance at low cost. Because of this I think it has potential as a low cost alternative to Nylons while also having good heat resistance. So I don’t disregard the material completely, but I do think there are better options. PLA+ is better in all respects save for heat resistance.

PETG has poor mechanical properties. It’s largest problem is with impact resistance. If you bend or feel a PETG part, it appears ductile and you would think impact resistant. However, under sharp impact, PETG shatters and has very poor impact resistance.

PETG does have better temperature resistance then PLA+, but it’s not enough to make it usable. I would use ABS over PETG for mechanical parts. For non mechanical parts, it can be great. Just not the right thing for high stress parts.

This depends on what Super Lower you want to print. The single rib Super Lower will work with almost any AR-15 upper receiver. However, the double rib lower must be used with slick side uppers that do not have a forward assist. Mil-Spec uppers will work with the single rib lower, as will Aero Precision M4 uppers. The Bear Creek Arsenal side charging uppers will work with the double rib lower. As long as the upper is compatible with a standard “Mil-Spec” AR-15 lowers, and you consider the above mentioned caveats related to the forward assist, then you should be good. Any AR-15 caliber should work, including 5.56 x 45, 22 LR, 5.56 x 35, and 7.62 x 39, if the right mags are used.

Here are a few options for uppers.

I really like these Aero Precision uppers: https://www.aeroprecisionusa.com/m4e1-threaded-16in-556-mid-length-complete-upper-atlas-rone However, they are a bit more expensive because you have to buy a separate Bolt Carrier Group (BCG): https://www.aeroprecisionusa.com/5-56-bolt-carrier-group-complete-nickel-boron

BCA makes really cheap uppers that will work, but quality can be (is) lacking: https://www.bearcreekarsenal.com/guns-parts/ar-15/ar-15-complete-upper-assembly/556-16-parkerized-m4-barrel-1-9-twist-carbine-15-handguard-scg2-nrail-spiral-flash.html

And there is always PSA, they sell quality parts for a lower cost: https://palmettostatearmory.com/psa-16-mid-length-5-56-nato-1-7-nitride-13-5-lightweight-m-lok-upper-with-nickel-boron-bcg-ch-5165449606.html

Remember to always check to see if the upper come with a BCG, not all do.

And if you want to assemble your own upper from parts, KAK is a great company. 

LR-308 parts are very confusing. There are a number of standards, and many of the parts are not interchangeable. I would only use parts that are specifically “LR-308” or “DPMS” compatible. Palmetto State Armory PA-10 kit’s are a notable example of a kit that is not compatible, the bolt hold open lever is the wrong size to work with my LR-308 lowers. I would recommend using lower parts from KAK, or just pick up one of my 308 Combo Kits.

LR-308 uppers are not as simple as AR-15 uppers. There are a number of standards. My LR-308 Super Lowers are designed to use the LR-308 / DPMS standard. Unfortunately, not all companies properly name their uppers, so care is needed. Bear Creek Arsenal, Aero Precising, and KAK all make LR-308 uppers that will work with my lowers. Bear Creek incorrectly calls them AR-10, and Aero calls theirs M5. True AR-10 uppers will not work. Below is a more in depth video.

Yes. 300 AAC Blackout does not place additional stress on the lower over 5.56 x 45. In fact, your gas system and buffer mass are much larger factors in how much stress is placed on the lower receiver. A heavy buffer with a lot of gas on a 5.56 gun will place more stress on the lower then a light buffer properly gassed on a 300 Blackout gun.

There are a ton of options, your budget and goals will determine which you buy. I use the Prusa i3 MK3, a great machine, though a bit out dated by todays standards. The Ender 3 line of printers from Creality is extremely popular for a reason, because they are low cost and can work quite well. Though be warned, some tinkering will be required. There are many Ender clones on the market that are a bit better or worse, watch a few reviews before buying. A printer like the Bambu Lab X1 would be a great option for out of the box printing, though you will pay more.

We use Prusa i3 MK3 printers for most parts. I also use an Ender 3.

I use the E3D NozzleX. Brass Nozzles will work great with non abrasive filaments, but I highly recommend a hardened nozzle if you are going to print any filled materials. Stay away from low quality off brands if you can, a bad nozzle will insure a bad print.

0.4 MM is the standard that most models are designed for. 0.6 MM will also work in many cases, but check the documentation to see if it’s compatible. 0.25 MM nozzle are great for fine detail on some parts, but are not needed unless specifically specified.

We use Solidworks for all design work.

Because of the drawbacks being greater then the advantages. However, I don’t know of all the clamp types. So if you see a uncommon clamp that you think will work, let me know! If it’s a common type, I’ve probably already checked it out.

Before you can find a better solution, you have to find the problems with the current one. The issue with the worm-drive clamp is that the drive mechanism is large and protrudes from the side of the lower. That’s it. So for any other solution to be better, it needs to be more streamlined, while also meeting all of the requirements that the worm-drive clamp meets.

Other clamp types don’t meet both of these requirements. Common problems:

• Not more streamlined.
• Too thick / stiff to conform to the non-round section of the buffer tower.
• Not as strong

Not to say that there are not better options to the hose clamp! There are, and I am working on it 😉

Short answer, no. Long answer, it won’t hurt until you need to replace or remove the ejector. On my AR-9 designs the ejector is 3D printed, it presses into a pocket on the lower. This may be concerning to some users, as it appears to only be a friction fit holding the part in. However, if you look closely you will see that the upper receiver holds down the edge of the ejector when the upper is installed, this locks the ejector in place so that it can not escape. I do not recommend glue.

I stopped using washers on the bushing installation tools some time ago. This was because the benefit was not worth the trouble. The washer is hard to install, easy to lose, and without it the tool does no significant damage to the surface of the lower. So no more washer!

As of now, 3D printing your own firearm is legal under federal law. However, a number of states do regulate or outright ban the home manufacture of firearms. You will have to check your state law.

We removed the files for the original forced reset trigger design after receiving a cease and desist letter from Rare Breed Firearms claiming patent infringement. There is a new, better design in the works now.