• Customizable Length of Pull (12" to 14.25") with included shim set
  • Combines the versatility and adjustability of a collapsible stock with the strength, ergonomics, and solid fit of a fixed stock
  • Modular assembly
  • HK Hook attachment and sling loop
  • Install on carbine-length / A5 buffer tubes
  • Available in Black and Flat Dark Earth finish!
  • Compatible with Strike Industries MFS Extended Rubber Butt Pad and MFS Monopod (Optional)


  • Weight: 12.63 oz. (with mounting hardware and shim set)
  • Material:
    • Stock: Polymer
    • Mounting Hardware: Steel
  • Length:
    • Min: 9"
    • Max: 11.25"
  • Height: 5.13"
  • Width: 1.75"


  • Mil-Spec carbine-length and A5-length buffer tubes


  • 1x Modular Fixed Stock
  • 1x Stock Front Piece
  • 3x Adjustment Shims (0.75-inch)
  • 1x Carbine-Length / A5 Buffer Tube Adapter
  • 1x Adapter Screw


If you’re a fan of the personal defense or close quarters CQB stock and you need an AR-15 Fixed Stock, Strike Industries has heard your cries. The Modular Fixed Stock brings options for versatility and adjustability to the table along with the solid fitment, ergonomics, and hardiness of a fixed stock.

Fixed Stock, Custom Pull Length

The Strike Industries Fixed Stock accepts standard carbine length receiver extensions. When you need an AR fixed stock for an existing weapon, it’s no problem to fit an SI MFS. All you need to do is choose your desired length, install the correct spacing shims and you will have a custom length of pull and an AR-15 Fixed Stock that holds rock solid even under extreme operating conditions. As packaged the MFS is easy to customize in ¾-inch increments from 12 inches to 14.25 inches length of pull.

Polymer Construction with the Security of Steel

The Strike Industries Modular Fixed Stock features the light weight of a polymer AR Fixed stock with the security or quality steel mounting hardware. Strike delivers exactly what you need. Fit, feel, and reliability without compromise.

Field Ready Design

The field ready design of the Strike Industries Modular Fixed Stock requires no additional sling mounting hardware. It features an integrated HK hook Attachment and sling loop. Since you’re working with a solid stock you won’t have to quiet odd rattles when you’re on the move and there’s no worry about catching a latch and pulling up at the wrong length. Simply mount the SI MFS up at your desired length, clip on your favorite sling and you’re mobile, ready for whatever the next maneuver brings.


  1. Slide the front piece onto the carbine-length buffer tube until it touches the castle nut
  2. Install the buffer tube adapter on the first slot of the buffer tube
  3. Add adjustment shims if needed
  4. Install the Modular Fixed Stock onto the buffer tube
  5. Remove the rubber butt pad
  6. Use the adapter screw to secure the stock

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