The B5 Systems Sierra K Receiver Extension Stock for B5 Systems Sierra K Extension is a stock that fits B5 Systems Sierra K Extension, offered in Black, Coyote, Olive Drab Green.
The Sierra K is a purpose-driven compact stock, optimized for use on PDW and compact weapon systems. Features include reduced overall size and slim cheek profile, snag-free adjustment lever, limited rotation QD and integral fixed sling mounts, internal tensioners, and anti-slip buttpad. Mounts via shortened compact Mil-Spec receiver extension.
The stock sets your length of pull and cheek position, so it has a direct effect on how consistently you can build a position behind the rifle. Collapsible AR-15 stocks slide on to the buffer tube (receiver extension) — check whether your rifle has a mil-spec or commercial diameter tube, as the two are not interchangeable.
How It Compares
Also compare the Sierra K Extension Kit for AR15, Collapsible Precision Stock for AR-15, Short and Collapsible Precision Stock for AR-15, Medium. Browse all stocks & Chassis and the full B5 Systems range.
Ideal For
- PDW and compact weapon builds that need a slim, short stock
- Rifles fitted with the B5 Systems Sierra K receiver extension kit
- Shooters who want a snag-free, low-profile adjustment latch
- Builds in Black, Coyote or Olive Drab Green
Key Features
- Optimized for PDW and Compact Weapon Systems
- Low-Profile Adjustment Latch
- Slim-Profile Ergonomic Cheek Weld
- Color-Matched Steel Hardware
- Ambidextrous Fixed Sling Mounts and Limited Rotation QD Mounts
- Mil-Spec Materials and Finishes
- Mounts via Sierra K Receiver Extension Kit
- Available in All Standard Colors
- Weight: 6.6 oz
- Length: 5.63 in
Compatibility & Fitment
Fits B5 Systems Sierra K Extension. Not sure it fits? Contact us before you order and we will check for you.
Technical Specifications
Brand | B5 Systems |
Type | Stock |
Model | Sierra K |
Colors | Black, Coyote, Olive Drab Green |
MPN | SRK-1655, SRK-1657, SRK-1658 |
UPC | 814927024748, 814927024762, 814927024779 |
US Shipping & Support
Genuine B5 Systems, brand new and covered by the manufacturer's warranty. Shipping is free on US orders of $99 or more, and smaller orders ship from $6.95. Questions about fit, mounting or which option suits your setup? Our team is glad to help before and after your purchase.
Frequently Asked Questions
What colors is it available in?
Black, Coyote, Olive Drab Green. Choose your color from the options above.
What does the Sierra K Receiver Extension Stock fit?
Fits B5 Systems Sierra K Extension.
Is this a genuine B5 Systems product?
Yes. It is a new, genuine B5 Systems product sourced through an authorized US distributor.
How much is shipping?
Shipping is free on US orders of $99 or more. Orders under $99 ship at a flat rate from $6.95 to $9.95, depending on the order total.
