What is a K-SPEC BCG (Bolt Carrier Group)?

The K-SPEC BCG combines multiple key features focused on increasing the reliability of your AR15 style firearm no matter if you are running suppressed or unsuppressed, and regardless of conditions. The K-SPEC is a truly plug and play BCG that will accommodate whatever configuration your mission requires.

For those running suppressed, the K-SPEC requires no additional tuning or tweaking of the gas or recoil systems to run reliably. Like all KAK BCGs, the K-SPEC is machined to the M16 full auto profile.

Both the K-SPEC Carrier and K-SPEC Bolt are backwards compatible with all standard mil-spec BCG components. The K-SPEC bolt can be used in any AR15 style direct impingement system, and the K-SPEC carrier will function perfectly with any standard AR15 bolt.

Because we manufacture our BCG components in-house and do not rely on outsourcing, KAK Industry is able to offer the K-SPEC complete BCGs and components in over 50 combinations from 5.56 NATO all the way to .458 SOCOM, in multiple finishes, and left-hand versions as well.

Slotted Angled Carrier Rails

For enhanced functionality in adverse and rugged conditions such as sand, mud, dirt, and grime. These rail cuts are designed for debris disbursement, resulting in ultra-high functionality in the toughest conditions, including suppressor fouling and foreign contaminates. Strategically located angle cuts in the rails result in fouling and debris being moved into noncritical areas that are not in contact with the receiver and do not affect the function of the firearm.

The slotted angles on the bolt carrier group also contribute to weight reduction and enhanced maneuverability. By removing material in strategic areas without compromising structural integrity, the overall weight of the BCG is reduced, which can positively impact firearm handling and balance.

In an effort to reduce the amount of debris and gas vented towards the shooters face, the two standard gas relief ports have been relocated from the ejection port side of the K-SPEC carrier and placed underneath, resulting in downward gas venting through the magwell.

Downward Gas Vents

In an effort to reduce the amount of debris and gas vented towards the shooters face, the two standard gas relief ports have been relocated from the ejection port side of the K-SPEC carrier and placed underneath, in the magazine feed lip channels. Two additional emergency relief ports have also been added to the bottom of the carrier to mitigate structural damage in the event of a case head separation. Testing has shown that venting the gasses through the magazine well has no negative impact on the feeding or function of the magazine nor ammunition, and any added heat is negligible.

Dual ejectors

The K-SPEC dual ejector system uses mil-spec ejectors and springs that require no proprietary parts. Ejector holes are centered on the lugs to avoid any reduction in strength of the bolt. The dual ejector system increases the ejection reliability and adds consistency to the ejection pattern. KAK Industry has been manufacturing dual ejector bolts for the AR10/LR308 platform for over a decade and has used that experience to create a durable and reliable dual ejector system for the AR15 platform.

With two ejectors positioned on the bolt, they work in tandem with the extractor to eject spent casings through the ejection port for consistent, smooth and reliable ejection. This redundancy can be beneficial in scenarios where the firearm might experience adverse conditions, such as dirt, debris, or variations in ammunition. The dual ejectors provide added assurance that spent casings will be properly ejected, minimizing the risk of malfunctions or failures to eject.

In summary, dual ejectors on a bolt carrier group provide an additional level of reliability and consistency in the ejection process. By incorporating two ejectors, the bolt carrier group ensures positive ejection of spent casings even in adverse conditions.

KAK Industry K-SPEC BCG (Bolt Carrier Group)

• Designed to function reliably in the toughest conditions
• Optimized for both Suppressed and Un-suppressed use, All uses – All Conditions
• Dual Ejectors for enhanced reliability
• Angled Carrier Rail Cuts for flawless function in adverse conditions and prolonged suppressed use
• Downward Gas Ports to reduce gas blowback to shooter
• Full Auto Profile
• Permatex added between Gas Key and Carrier Mating Surface
• Carrier- 8620 steel, outside rails, bolt runs, and gas bores ground to .0002 tolerances, nitride finish
• Bolt- 9310 steel, outside diameters ground to .0002 tolerances, MPI test, nitride finish
• Firing Pin- 8740 steel, Swiss turned, heat treated, precision ground, chrome plated
• Cam Pin – 4140 steel, Swiss turned, heat treated, nitride finish
• Extractor- 4140 steel, fully machined, Phosphate coated
• Extractor pin- S7 tool steel, ground, heat treated
• Ejector- S7 tool steel, ground, heat treated
• Gas key – 4130 steel, heat treated, secured with T25 torx fasteners, torqued to spec, staked with in house hydraulic staking machine

K-SPEC Frequently Asked Questions

Q: How is the blowback into the magazine, or do they point around the side of it?
A: It does not effect the function. There’s no measurable increase of blowback debris we could find in our testing.

Q: KAC knock off?!?! 😂
A: The one similarity are the slotted carrier rails, which FALs had in 1960.

Q: How about the cam pin path? Modified or no?
A: Standard cam path to the mil drawing.

Q: What’s the round count before it affects reliability? Compared to side vent BCG round count.
A: We have not had any stoppages from the down vents effecting the ammo or magazines.

Q: Would chrome plating ever be on the menu for these BCGs?
A: Chrome, np3, chrom phos, chrom, and a few dlc option will be brought to market. We’ll have a wide variety of finishes down the line.

The K-SPEC Clear Mag Test

The K-SPEC Egg Test

Machined in-house and assembled using only the finest steels and components.

KAK Industry takes pride in producing some of the finest Mil-Spec / Enhanced AR15 bolt carrier groups available, made 100% in-house at our MO facility using Doosan machining centers, Tsugami Swiss turning, and the latest in FANUC robotics combined into an automated cell giving us lights out production capability. In-house automated CMM inspection processes ensure consistent quality.

You can download our K-SPEC key features in PDF here.

Have any questions on our new K-SPEC? We’d love to hear from you. Ask away in the comment section below.

Elyssa McGregor

Elyssa is the Information Technology Manager at KAK Industry. She blends her tech expertise with a passion for the firearm industry. She thrives on crafting innovative ideas and conducting research for engaging blog posts and marketing materials. Elyssa's unique approach reflects her dedication to both technology and the firearms community.

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