The Gen 2.1 KRISS Vector CRB and Vector SBR (non-folding stock version) are equipped with a mil-spec AR carbine buffer tube. This tube is used to mount the KRISS DS-150 adjustable stock.
If you’d like to switch to a different stock option—such as the KRISS Vector Ambidextrous Folding Stock - the AR buffer tube can be easily removed.
Safety Procedures
Before performing any maintenance:
- Remove the magazine
- Visually and physically inspect the chamber to ensure the firearm is unloaded
Tools Required
- 1.5mm allen key
- AR-15 armorer's wrench
Buffer Tube Removal
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Step 4 The upper is now ready to accept a new stock solution. |
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Step 1 Locate the two set screws on the underside of the upper receiver. Using a 1.5mm Allen key, loosen and remove both screws to release the buffer tube. |
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Step 2 Use the AR-15 armorer's wrench to loosen the castle nut. It is standard threaded (anticlockwise to loosen). |
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Step 3 Unscrew the AR carbine buffer tube from the upper. It is standard threaded (anticlockwise to loosen). |
What About the Set Screws?
The set screws you removed are not required when installing the KRISS Vector Ambidextrous Folding Stock or the KRISS Vector Ambidextrous Folding Adapter.
These screws function only as anti-rotation aids for the AR carbine buffer tube. Since both the folding stock and adapter use an offset mounting screw, they are securely fixed in place and cannot rotate once installed.
What to Do with the Set Screws:
Store them in a safe place for future use.
Optionally, you may reinstall them into the upper housing after installing your new stock setup.
Important
If you choose to reinstall the screws, do not overtighten. They thread into polymer and can strip easily with excessive torque.