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BKF M4 MOD-1 Reduced Power 8-POS Buffer Assembly – Sprinco Spring (Yellow), BKF Lightweight Buffer (2.7oz)

(1 customer review)


41 in stock



All of our springs are constructed from Certified Chrome Silicon wirestock to ISO 9001:2008 quality standards to withstand extreme heat and highly cyclic rate. The certification rating ensures a consistency in the parent material of 95%, which translates to repeatable consistency in performance & function. Certified Valve Quality Chrome Silicon wire is used in very high stress applications such as, NASCAR, Formula One, Moto GP & Pro Stock racing motor valve springs. It is not uncommon in some of these applications for valve springs to see 15,000,000 compression cycles in one race. It is this extraordinary capability that makes Chrome Silicon wire the obvious choice in our spring production vs. music wire or 17-7 PH used in OEM springs and by most aftermarket competitors. In addition, all of our Chrome Silicon buffer springs are heat treated, stress relieved, and dual-stage shot peened in separate post winding treatments. We also treat each spring with a proprietary, deep-penetrating, Re-Micronized (to .3 Micron particle size), inhibited, Molybdenum-Disulfide (MoS2) formulation to eliminate 90% of all mechanical wear on the spring. The combination of materials & processes result in a loss of no more than 5% in spring efficiency. The minimum anticipated duty cycles of our buffer spring designs are in excess of 1,500,000 cycles.


  • ASTM Grade A877 Certified Valve Quality Chrome Silicon Wirestock
  • Heat Treated, Stress Relieved and Dual Stage Shot-Peened post winding (Our springs really ARE shot-peened)
  • Impregnation / Plating with Re-Micronized Molybdenum Disulfide formulation
  • Hard plastic tube packaging for protected transport and easy storage
  • Optional Cryogenic Processing available upon request


  • Shortened “lock time” for faster sight recovery and platform stability
  • Consistent spring pressure throughout the duty cycle of the spring, resulting in fewer malfunctions related to spring operation. (Especially Type III malfunctions)
  • Improved & consistent cyclic operation. Spring will not change performance for many hundreds of thousands of rounds.
  • Greater resistance to heat induced performance degradation
  • Reduced cyclic rate with Enhanced or Extra Power springs and reduce / eliminate bolt bounce with optimal spring / buffer weight selection.
  • Reduced operating cost as replacement springs are not needed during the life of your upper receiver assembly. Less downtime and fewer trips to the armorer for spring replacement, in fact, this will most likely be the only buffer spring you will ever need for the duty cycle of your carbine or rifle!
  • Correct spring selection works reliably, consistently, and virtually indefinitely in all properly built and maintained AR platforms.


  • BKF MOD-1 AR15 Fluted 8 Position Anti-Tilt Carbine Length Buffer Tube
  • BKF Lightweight buffer W/ Steel Weights (1)and 1 Aluminum weight (2.7oz)
  • Sprinco Reduced Power Buffer spring (Yellow)
  • Steel Mil Spec end plate and Mil Spec locking (castle) nut – Phosphate Coating
  • Made in the USA

BKF MOD-1 AR15 Fluted 8 Position Anti-Tilt Carbine Length Buffer Tube Features include:

  • Billet machined from 6061-T651 aluminum for tighter concentricity than a forging or impact extrusion to reduce potential for bolt carrier binding.
  • 8 position adjustment with machined indicators visible through any stock with a viewing port located at the stock latch pin. Extended positions, increment adjustments have a finer spaced length of pull.
  • Mil Spec extension diameter of 1.148, and thread diameter of 1.185
  • Carbine length
  • Extended carrier support flange that supports the carrier for better anti-tilt performance.
  • Self aligns with the buffer detent.
  • Fluted for a more aesthetic look
  • Chamfered edges on the stock guide ramps for better feel
  • 3 Drain holes at 6 O’clock
  • Weight 3.45 oz
  • Proudly made in the USA!!!

Sprinco Spring:

  • YELLOW:  Reduced Power Spring

Useful for under gassed rifles, such as some mid-length gas rifles, “Dissipator” builds or 300 blackouts that short stroke or have weak ejection patterns trying to shoot subsonic’s without a suppressor. 

Lightweight Buffer:

AR15 Lightweight carbine buffer for use in AR15 carbines with a collapsible Carbine buttstock. These are made for tuning specialty subsonic loads in platforms like 300 BLK. It is not recommended to use with full power loads.

Additional information

Weight 1 lbs
Dimensions 10 × 4 × 2 in

1 review for BKF M4 MOD-1 Reduced Power 8-POS Buffer Assembly – Sprinco Spring (Yellow), BKF Lightweight Buffer (2.7oz)

  1. Ronald M. (verified owner)

    Got this as a present for my wife’s AR it was just what she needed for her stock

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