The B5 Systems Sierra K in coyote brown is a purpose-built compact rifle stock designed for shooters running short-barreled rifles, PDWs, and other space-constrained platforms. Unlike full-size stocks, the Sierra K prioritizes a reduced footprint and slim cheek profile—critical features if you're working with a compact receiver extension or building an ultralight, maneuverable rifle. It's the kind of stock you choose when every inch and ounce matters, whether you're running a dedicated close-quarters carbine, a truck gun, or a suppressed short-barrel setup.

The Sierra K mounts via B5's shortened compact Mil-Spec receiver extension, so confirm you have the right tube before ordering. The stock itself handles adjustment cleanly: a snag-free latch means no accidental movement during handling, and the design keeps cloth, slings, and gear from catching during transitions. You get integrated fixed sling attachment points built right in, plus QD capability with limited rotation—that's purposeful mounting, not afterthought holes. B5 finished it with color-matched steel hardware and an anti-slip buttpad so the thing stays planted against your shoulder or kit.

Build quality is straightforward: Mil-Spec materials and finishes mean this stock will take a beating without looking shabby next year. Internal tensioners keep everything tight during use. The coyote brown finish is practical and subdued—it won't stand out in a rifle bag or call attention on the clock.

Key Features

• Compact profile optimized for PDW and short-barreled rifle builds
• Slim cheek design reduces overall footprint
• Snag-free adjustment latch prevents unintended movement
• Integrated fixed sling mounts with QD capability (limited rotation)
• Anti-slip buttpad for secure shoulder contact
• Color-matched steel hardware and Mil-Spec finishes
• Internal tensioners for solid, rattle-free assembly
• Mounts on B5 compact Mil-Spec receiver extension (not full-size tubes)

Specifications

Brand	B5 Systems
Model	Sierra K (Srk1657)
Color	Coyote Brown
Compatibility	B5 Sierra K Receiver Extension Kit (compact Mil-Spec)
Material/Finish	Mil-Spec materials with color-matched steel hardware
Sling Attachment	Integrated fixed mounts; QD-compatible (limited rotation)

Frequently Asked Questions

What receiver tube does the Sierra K fit?

The Sierra K is designed to work with B5's compact Mil-Spec receiver extension, not standard full-size tubes. Make sure you have the Sierra K Receiver Extension Kit before purchasing the stock.

Is this stock good for PDW and short-barreled rifle builds?

Yes. The Sierra K is specifically optimized for compact weapon systems and PDWs where a full-size stock is impractical. The reduced profile and slim cheek design keep your overall footprint minimal without sacrificing stability or sling options.

Can I attach a sling to this stock?

The Sierra K has integrated fixed sling mounts built in, and it's QD-compatible with limited rotation. You'll have solid, factory-designed attachment points without drilling or jury-rigging.

What's included in the box?

The product provided contains the stock itself. Confirm whether the B5 Sierra K Receiver Extension Kit is included or must be purchased separately for proper fitment.