bubar10 ar10 308 3d

BUBAR10 AR308 STL Files

3D Printed AR10 lower receiver chambered in .308

BUBAR10 AR308 Details

The BUBAR10 is a 3D printable LR308-style lower receiver that has taken the firearms world by storm. It is a modified version of the UBAR, but with a twist – it uses simple hardware store metal parts to reinforce the lower.

These reinforcements solve the major design concerns that printed AR lowers face, making the BUBAR-10 a solid option for printable 308 lowers. At the core of the BUBAR-10’s design are simple yet effective reinforcements, including a U-Bolt to clamp the buffer tower down, two humps to spread bending force at the rear of the receiver, and two eye bolts to act as the front takedown lugs on the lower.

These enhancements greatly enhance the strength and durability of the lower, making it able to withstand pushup tests, drops, throws, kicks, and other hard abuse.

If you’re looking for a reliable and more high-powered 3D-printed firearm, the BUBAR-10 is definitely worth considering.

BUBAR10 AR308 in the Wild



BUBAR10 AR308 Tech Specs

The Bubar10 AR308 is a 3D printable lower receiver designed to be used with LR308-style uppers.

However, the AR10 platform lacks proper standardization, with two prevailing specs (LR308 and Armalite spec) that vary from one manufacturer to the next. The rifle’s design is based on the PSA AR-10 uppers, but outside of those, fitting or purchasing additional parts may be required.

The Bubar10 AR308 is designed to use carbine buffer tubes/buffers only, as the U-Bolt reinforcement doesn’t work well with the shorter threaded section on rifle gas tubes. The firearm is compatible with any length upper/gas system as long as a carbine buffer and spring are used.

The Bubar10 AR308 has been tested with standard PMAGs, which seem to be compatible across the board.

Required Parts for the BUBAR10 AR308


  • Filament
  • 3D Printer
  • AR10 Complete Upper
  • AR10 Lower Parts Kit
  • AR15 Stock
  • AR10 Buffer & Buffer Spring


  • U-Bolt
  • 2 x Rod-End Eye Bolts
  • 1x 9/32” OD 1/4” ID Brass Bushing, 0.745”
  • 1x 9/32” OD 1/4” ID Brass Bushing, 0.495”
  • Extended Length Front & Rear Takedown Pins


  • Drill bits 1/4″, 5/32″, 3/8″
  • Dremel Tool
  • Dremel Cutoff Wheel
  • 1/4 x 28″ Tap
  • Needle Nosed Pliers

Suggested 3D Printed BUBAR10 AR308 Settings

Nozzle0.4 mm
Layer Height0.15 mm
Tempreture230 F / 60 C
Infill Density100%
SupportsOn / Full
Support TypeTree
Bed AdhesionGluestick / Hairspray


  • PLA+ (eSun, Polymaker Pro or stronger)

Looking to make your local boomer at the gun range s*** their pants? The BUBAR10 AR308 is guaranteed to leave a mark (or several).

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Dan M.
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