Luth-AR Releases Carbine Stock Compatible MBA-3

Nathan S
by Nathan S

Luth-AR the latest start-up by Randy E. Luth, is now offering their latest version of their MBA or “Modular Buttstock Assembly”. The MBA-3 is the aptly named 3rd version of the stock system, keeping with the same philosophy of minimal weight and parts. Unlike the MBA and MBA-2, which were designed for standard rifle receiver extensions, the MBA-3 is multi-position carbine stock ready.

Over its earlier-released siblings, the MBA-3 includes a bottom-mounted picatinny rail for mounting monopods or similar accessories. As a bonus, the MBA-3 adapts to both commercial and mil-spec tubes but it comes with a warning that it may not fit certain “oversized” extensions designed to tighten up stock fitment.

I find the MBA’s to be a nice contrast to the MagPul PRS offering. While the MBA series does not offer the immediate adjust-ability, a rifle tends to be adjusted once and left there for its service lifetime. On the flip side, the PRS is completely self-contained and adjustments are easy versus the MBA, which uses knobs and nuts to hold itself together, which can get lost during adjustment if one does not pay close attention to the little buggers. To see one mounted to a billet rifle, check out our review of the JL Billet handguard.

Those interested can check out LUTH-AR and pick one up from the directly or through various reta ilers.

Product Description from LUTH-AR:


The MBA-3 includes the following features:

  • Buttstock assembly to mount to a Carbine AR
  • Fits all .223 and most .308 AR style rifles
  • Easy to Replace and quick to install
  • It adds up to 1-inch of height on the cheek rest, and an additional 1-1/16 inch length of pull
  • Made of super strong glass-filled nylon, the Luth-AR MBA-3 weighs roughly half that of comparable stocks coming in at just 18 ounces.
  • Includes a Picatinny Rail on the bottom rear of the Stock Body to attach your choice of many accessories.
  • Designed a flat bottom index set screw (10-24) to eliminate that constant rattle of carbine collapsible buttstock. This also allows you to secure the stock in your favorite position.
  • 3-axis adjustable butt plate assembly (keep in mind this butt plate assembly is interchangeable with the original MBA-1 Buttstock) will have the following movement:

    Horizontal for linear adjustment (i.e. length of pull)Vertical for a perfect butt plate fit into the curvature of the shoulder.Lateral adjustment for a ½ inch left or right cast.

  • Ergonomic
  • Adapts To Existing Commercial and Mil-Spec Buffer Tubes
  • Certain after Market Commercial Buffer Tubes that exceed 1.172″ may not fit
  • The MBA-3 and MBA-4 will come in black. Flat dark earth and Pink will be available in a few more months


  • Length of Pull (LOP) – Extended: 15 5/8″
  • Length of Pull (LOP) – Collapsed: 11 11/16″
  • Overall Length Extended: 8 3/4″
  • Overall Length Collapsed: 7 11/16″
  • Weight: 18.5 ounces

*Length of Pull Specs depend on Buffer Tube Hole Location/Position and 5 or 6 hole patter.

Additional Information

It does not include the following, but can be purchased separately in the accessories section:

  • Sling Swivels
  • Carbine Buffer tube
  • Carbine Buffer Body
  • Carbine Buffer Spring
  • Latch Plate
  • Lock Ring

Installation Notes: When tightening the anti rattle set screw, be careful not to over tighten as it may cause the threaded insert to separate from the plastic stock body.

Nathan S
Nathan S

One of TFB's resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR's, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.The above post is my opinion and does not reflect the views of any company or organization.

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