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3D Printed AR15 Lower (5 Best)

3D printed AR-15 lowers used to be the thing of pipe dreams.

However, those dreams have become a reality with the invention of 3D printed AR-15 platforms like the UBAR, U-Bolt Vanguard, Hoffman Tactical, and Firebolt lower frames.

3d printed ar15 lower best

In the last 2 to 3 years, 3D printed gun design has skyrocketed and opened the floodgates for many excellent gun printing options.

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When the first 3D printed AR-15 lower came online, it took the internet by storm and helped to inspire other 3D gun developers to push what was thought possible even further.

In 2022 there is now a wide range of 3D printed AR options, from the customizable to the reinforced, and even meme options like the double-barreled AR-15.

If you are trying to decide which AR-15 lower to print for your needs, continue reading as we deep dive and cover all of the AR lower 3D printing options available today.

UBAR 2 3D Printable AR15 Lower

ubar2 ar15 1

UBAR 2 STL Files

The UBAR 2 is a 3D printable AR15 lower receiver. It is an evolved version of the U-Bolt Vanguard lower – more straightforward to assemble, more robust, and compatible with a wider variety of AR15 parts.

The UBAR is a guaranteed solid choice designed by Ivan the Troll, one of the best 3D printed gun developers to hit the scene.

At the core of the UBAR’s design is its simple reinforcements – using hardware store metal parts solves the major design concerns that printed AR15 lowers face. 

Using a U-Bolt to reinforce the rear tower and rod end eye bolts to reinforce the front takedown lug, the UBAR is a contender for the strongest printable AR15 lower design at its time of publication.

Printed Parts Checklist:

UBAR2 Lower Receiver

Four variants are the UBAR2, and four are the UBAR2C – the “C” designation indicates that the lower has a little extra clearance required for some side charging/billet/nonstandard uppers.

UBAR2 and UBAR2C have four sub-variants: high-shelf options and low-shelf options. Print one of the low-shelf models if you use an FRT trigger or other device requiring a low-shelf receiver. 

Otherwise, the standard lowers will be more robust (since lowering the shelf increases a stress concentration in the lower).

ubar 2ar15 frame 2

For all the high and low-shelf variants, there are two sub-variants – lowers that have a cutout for the forward assist, and lowers that do not. Print the forward assist version if you have a forward assist installed on your rifle. 

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If you have a side charging AR, one without a forward assist, or you removed/plugged your forward assist, you can print the no forward assist version, as it will be slightly stronger.

General Print Settings:

The UBAR 3D printed lower AR receiver has been tested to work well in eSun PLA+. This receiver should also work in any material similar to or superior to PLA+.

Walls: I used 8, but you can use whatever works best for your setup.

Nozzle: 0.4mm

Layer Height: 0.15mm or 0.16mm

Temp: 230/60C

Infill: 100% Recommended – while the UBAR might not need 100% fill, this ensures that you won’t end up hurting the lower if you overtighten anything.

Supports: On/full (tree supports are ok)

Cooling fan: 20% normal, 50% on bridges. Off for the first 10 layers. Keep the fan speed low to prevent warp.

Bed Adhesion: gluestick or hairspray recommended

All other settings can/should be left as default or whatever you know works best with your printing setup.

U-Bolt Vanguard AR-15

u bolt vanguard ar15 3d

U-Bolt Vanguard

The U-Bolt Vanguard is yet another 3D printed AR-15 lower designed by Ivan the Troll.

The U-Bolt Vanguard is updated and modeled after the original Fosscad V5.1 GS AR design.

This AR lower tested up to 2000 rounds of 5.56 ammunition and showed no signs of structural integrity loss.

This AR frame only works with carbine and pistol buffer tubes.

u bolt vanguard ar

While the U-Bolt is quite bulky for your typical AR-15 lower, it is reinforced, bulked up, and modeled for maximum compatibility with the Colt M4 TDP, which helps assembly go a little smoother.  

Also, note that the buffer tube threads modeled here are NOT to spec but are instead modeled so that they can be printed and used without tapping.

If you want a choker of an AR-15 that will hold up and sh** on the funds who claim 3D guns will blow your hand off, the U-Bolt Vanguard is a great AR lower printed pick.

Firebolt AR Lower

firebolt 3dprinted ar

Firebolt AR Lower

The Firebolt AR-15 lower is one of the go-to choices for those that want both durability, modularity, and customization.

The Firebolt is printed in several different pieces and then bolted together. Hence the name “Firebolt”.

The Firebolt AR lower is totally 3D printed and compatible with a ton of uppers/calibers, including .223 (AR-15), 9mm (AR-9), and .45 (AR-45).

The “buffer tower” also allows for many options on the Firebolt, including the standard buffer tube reinforced with a “U” bolt and a 100% printed buffer tube.

3d printed firebolt ar15

The Firebolt, its predecessor, the thunderbolt, and the AR-15 waffle magazine were all designed, printed, and tested initially by 3D gun developer SpookySpectre.

If you are looking for reliability, strength, and a bit of customization, the Firebolt AR lower has you covered.

Hoffman Tactical 3D Printed AR-15

hoffman tactical ar15 superlower

3D Printed AR-15

Hoffman Tactical launched in mid-2019 focussing on mostly unrelated manufactured parts for various applications.

With the rise of 3D printing in 2020, Hoffman Tactical transitioned into 3D printing, which was soon followed by a focus on AR builds.

Hoffman Tactical, to date, has mainly worked on perfecting the AR-15, AR-9, and LR-308 3D printed lower receivers.

The Hoffman Tactical AR-15 lower is their “flagship” design. The HT AR-15 lower print files contain the Super AR-15 Lower(STL and STEP files), designed to be paired with their reinforcement kit. This 3D print download also includes the Basic AR-15 Lower, which requires some parts and a 2″ hose clamp.

Hoffman Tactical AR-9

hoffman tactical ar 9


The AR-9 lower(AR-15 style lower chambered in 9mm) is based on the Hoffman Tactical V3.0 Super AR-15 Lower. 

The AR-9 utilized Glock-style magazines and a 3D printed mag catch/ejector. The only non-AR-15 part required is the 3/32″ x 1″ roll pin for the mag catch.

Hoffman Tactical DOUBLE RIB AR-15

hoffman tactical ar15 double rib


The Hoffman Tactical Double Rib AR-15 Super Lower is named for its two ribs(stronger than one) and has an open right side for ambidextrous AR enthusiasts. 

The Double Rib AR-15 will not work with upper AR receivers that include a forward assist. A hose claim is also needed for this 3D printed AR-15 frame, but a bit larger at 28″. Slick sides and side chargers only.

Hoffman Tactical LR-308

hoffman tactical lr 308 3dprint


If you prefer to shoot bullets in 308 or 6.5 Creedmoor, the Hoffman Tactical LR-308 is the gun for you.

This 3D printed frame accepts LR-308 / DPMS Gen 1 / SR-25 upper. It is currently in version 2.6 and has stood up to a large amount of durability testing.

Double Barrel AR

The Double Barrel 3D printed AR may be in the running for meme gun of the year(although competition is high…looking at you, Ivan the Troll).

double barrel 3d print ar15

This print runs 2 3D printed AR-15 lowers and uppers in tandem with a connector making this the ultimate in-home defense.

Need mo’ firepower? The Double Barrel AR may be for you!


We hope you have learned something and gotten a bit closer to finally cranking up that Ender 3 and printing your own AR-15 lower at home.

Innovation is constant, and new 3D printed STL files are hitting the internet daily.

If you have a favorite AR-15 lower design or think we missed one of the great 3D prints, please drop a comment below.

Happy AR-15 building, blasting, and, most of all, meeting!

Written By

Cody Y.


Cody is a staff writer for 3D Gun Builder.

Cody brings years of experience in firearms, 80% builds, 3D printing, and internet security.

He owns six 3D printers and enjoys spreading his knowledge of modern day gun smithing around the world.

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