The KRISS Vector Ambidextrous Folding Adapter is an accessory for the Gen 2.1 KRISS Vector that allows you to add side-folding capability to an AR carbine buffer tube-mounted stock.

This accessory is not for use for the Gen 2.1 KRISS Vector Ambidextrous Folding Stock and cannot be used with the Gen 1 nor early Gen 2 KRISS Vector uppers. It cannot be used to adapt the Gen 1 / early Gen 2 Vector Hinged Folding Stock to the Gen 2.1 Vector.

Safety Procedures

Before you service your Vector, remove the magazine and confirm that the chamber is clear.

Tools Required

  • 1.5mm allen key
  • 2.5mm allen key
    • Only needed if you will be changing the folding direction.
  • 4.0mm allen key
  • AR-15 armorer's wrench

What is Included?

  • (1) Ambidextrous folding adapter
  • (1) Anti-rotation Set screw (preinstalled in adapter)
  • (1) Mounting screw
  • (1) Cosmetic ring

Changing Folding Direction

The adapter is configured from factory for the stock to fold to the right. If you wish to change the folding direction to the left, follow these instructions. Otherwise, continue to the next section.

Unscrew the push button with a 2.5mm allen key, then remove the adapter lock.


Rotate the adapter 180 degrees so the hinge is on the left. Insert the adapter lock through the underside and reinstall the button.


Test for function and confirm that the adapter folds and locks correctly.

Prepare Vector Upper for Installation

If you have a Vector SDP follow these instructions to remove the single point sling mount:
Removing Single Point Sling Mount from Gen 2.1 Vector Upper

If you have a Vector CRB or SBR, follow these instructions to remove the AR carbine buffer tube and KRISS DS150 stock:
Removing AR Buffer Tube from Gen 2.1 Vector Upper

Installing the Ambidextrous Folding Adapter

First, place the included cosmetic ring onto the adapter. An optional sling mount (sold separately) can be installed instead of the cosmetic ring.

Adapter 1.jpg Adapter 2.jpg

Set the included mounting screw into the adapter. There are two holes; only the upper hole is used for the mounting screw.

Adapter 3.jpg

Insert the adapter into the rear of the Vector's upper housing. Tighten the mounting screw using a 4.0mm allen key.

  • Torque spec: 6 Nm (53 in-lbs)

Adapter 4.jpg

Test the adapter and ensure that it is securely mounted and that the folding end moves and locks as expected.

Installing the AR Carbine Buffer Tube

Locate and remove the anti-rotation set screw using a 1.5mm allen key.

Adapter 5.jpg

Thread the buffer tube into the adapter. Once it is sufficiently threaded into the adapter, line up the notch in the buffer tube's threading with the threaded hole for the anti-rotation set screw.

Adapter 6.jpg

Lightly install the anti-rotation set screw and confirm that the buffer tube is aligned upright before tightening the set screw. Do not overtighten the set screw.

Tighten the castle nut using an AR armorer's wrench to slightly beyond hand tight.

Adapter 7.jpg