B5 Systems Sierra K Receiver Extension Buffer System
Mix and match across the range: 2 items save 5%, 3 save 10%, 4 or more save 15% on your whole basket.
Fits B5 Systems Sierra K Extension.
Not sure it fits your rifle? Ask us before you order
The B5 Systems Sierra K Receiver Extension is a buffer system fits B5 Systems Sierra K Extension.
The buffer tube (receiver extension), buffer and spring control how an AR-15 cycles and also carry the stock. Check the tube diameter (mil-spec or commercial) and length against your stock and rifle before ordering.
It is a genuine B5 Systems product, supplied new through our US distributor and offered in Black, Coyote, Olive Drab Green.
Fits B5 Systems Sierra K Extension. If you are unsure, contact us before ordering.
| Brand | B5 Systems |
|---|---|
| Model | Sierra K Receiver Extension |
| Type | Buffer System |
| Colours | Black, Coyote, Olive Drab Green |
| MPN | SRK-1655 · SRK-1657 · SRK-1658 |
Genuine B5 Systems. Order the B5 Systems Sierra K Receiver Extension Buffer System today — ordered in from the manufacturer for you and sent by Royal Mail Tracked 24, with delivery in 7–10 business days.
Explore more: Buffer Systems or browse all B5 Systems.
| Brand | B5 Systems |
|---|---|
| Model | Sierra K Receiver Extension |
| Type | Buffer System |
| Colours | Black, Coyote, Olive Drab Green |
| MPN | SRK-1655 · SRK-1657 · SRK-1658 |
| Category | Buffer System |
| Barcode | 814927024748 |
£5 tracked UK delivery on every order via Royal Mail Tracked 24. Our products are ordered in from the manufacturer rather than held in UK stock, so please allow 7 to 10 business days (Monday to Friday, excluding bank holidays) from the date of your order for it to reach you. Tracking details are emailed on dispatch. UK delivery only.
You have 30 days from receiving your order to cancel it for any reason, then 14 days to send it back unused and in its original packaging. Faulty, damaged or incorrect items are replaced or refunded and we cover reasonable return postage. Refunds go back to your original payment method within 14 days of receiving the return.
Black, Coyote, Olive Drab Green. Choose from the options above.
Fits B5 Systems Sierra K Extension.
Yes. It is ordered in new from B5 Systems through our US supplier, not a copy or a clone.
It is ordered in from the manufacturer for you and sent by Royal Mail Tracked 24, with delivery in 7–10 business days and £5 tracked UK delivery.
7 to 10 business days from the date of your order. Every order is sent Royal Mail Tracked for a flat £5 and you receive tracking details by email when it is dispatched.
Yes. We list only genuine parts and optics from the brands shown, ordered in from the manufacturer for your order.
Compatibility notes on this page come from the manufacturer. If you are unsure, email us with your make and model before ordering and we will check rather than guess.
Yes. Bundle & Save applies automatically in your basket: 5% off when you buy 2 items, 10% off at 3 items and 15% off at 4 or more. It works across the whole range, so you can mix and match, and there is no code to enter.
Yes — you have 30 days from delivery to cancel for any reason, as long as the item is unused and in its original packaging. See our returns policy for the details.
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