CMMG Pistol Tube Assembly — Black, with Ambi Sling End Plate — Fits AR-Platform (55CA67D | UPC 810103472808)
Build it right from the rear. The CMMG® Pistol Tube Assembly in black is a rugged, AR-platform buffer tube kit designed for reliability, clean aesthetics, and fast sling integration. Featuring a 1913-rail-free pistol receiver extension profile with an ambi sling end plate included, this assembly streamlines your next pistol build or retrofit by pairing proven CMMG quality with everyday installation simplicity. If you’re ready to complete your lower with parts that work as hard as you do, this is the kit to start with.
Why Choose the CMMG Pistol Tube Assembly
Purpose-Built for AR Pistols: A dedicated pistol receiver extension that’s strong, straight, and built to keep your setup slim and snag-free.
Ambidextrous Sling End Plate (Included): Mount a single-point or two-point sling from either side for quick shoulder transitions and confident weapon retention.
Durable Black Finish: Low-glare, corrosion-resistant coating blends with modern receivers and stands up to training, transport, and weather.
Drop-In Simplicity: Designed to fit AR-15/AR-pattern lowers with standard threading; install with common armorer tools and you’re range-ready.
CMMG Reliability: Manufactured to tight standards that support smooth cycling and long-term durability across round counts and range days.
Ideal Uses
New AR Pistol Builds: Finish a quality lower receiver with a matched pistol tube + ambi end plate in a single go.
Upgrades & Retrofits: Replace worn or budget extensions and gain ambidextrous sling capability for better handling.
Training & Home Defense Carbines (Configured as Pistols): Reinforced control and sling reliability matter when time and space are tight.
Compliance Note: Brace, stock, and overall pistol configurations are subject to current federal, state, and local laws. Before attaching any brace or stock, verify legality and classification changes that could reconfigure your firearm’s status.
Key Features at a Glance
Type: AR-Platform Pistol Receiver Extension
Finish/Color: Black, low-glare protective coating
Included: Ambi Sling End Plate (fits common QD or hook-style sling hardware depending on your sling)
Compatibility: Standard AR-15/AR-pattern lower receivers (common 1-3/16"-16 threading)
Manufacturer: CMMG
SKU / MPN: 55CA67D
UPC: 810103472808
Note: Castle nut and buffer/spring assemblies may be sold separately depending on package. Always confirm contents at point of sale.
Installation Overview (Quick Start)
Clear & Safe: Verify the firearm is unloaded and the workspace is clear.
Prep the Lower: Ensure the rear takedown detent spring and detent are accounted for; hold in place during installation.
Add the Ambi End Plate: Slide the ambi sling end plate onto the extension with the sling loops oriented to your preference.
Thread the Tube: Carefully thread the pistol tube into the lower receiver, capturing the buffer retainer and spring at the correct depth.
Secure: Align the end plate, install the castle nut (if included), and torque to spec. Stake the castle nut if desired.
Function Check: Confirm buffer retainer function, takedown pin/spring operation, and that the tube seats correctly without binding.
If you’re new to assembling lowers, follow a reputable armorer’s guide and use a torque wrench for repeatable results.
Performance Benefits You’ll Notice
Better Sling Control: The ambi end plate sets you up for stable shooting positions and smooth shoulder transitions.
Cleaner Ergonomics: Pistol-dedicated tube keeps the rear of your build simple, compact, and snag-resistant.
Repeatable Reliability: Quality extension alignment supports consistent buffer and BCG travel for smooth, reliable cycling.
Pairing Suggestions
Quality Sling: Choose a two-point convertible sling for maximum stability, or run a single-point for tight quarters (mission-dependent).
QD or HK Hook Hardware: Match your preferred attachment style with the ambi end plate’s sling locations.
Buffer & Spring: Pair with buffer/spring weights appropriate to your caliber and gas system to tune recoil and reliability.
Frequently Asked Questions
Q: Will this fit my AR-10/.308 build?
A: It’s designed around the AR-15/AR-pattern interface. Many .308 lowers share thread specs, but buffer length/weight differs—use parts matched to your caliber/system.
Q: Does it come with a castle nut and buffer/spring?
A: Packaging can vary. Some kits include those parts; others do not. Verify included components for SKU 55CA67D at purchase.
Q: Can I attach a brace or stock to this tube?
A: Attachment options depend on current laws. Review ATF guidance and local regulations before adding any brace or stock, as it may change your firearm’s legal status.
Q: Do I need to stake the castle nut?
A: Staking is recommended for duty/training use to prevent loosening under recoil and movement.
SEO Highlights (Naturally Integrated)
CMMG Pistol Tube Assembly black, ambi sling end plate included, fits AR-15/AR-platform, pistol receiver extension, AR pistol buffer tube kit, easy installation, durable low-glare finish, upgrade AR pistol sling mounting, SKU 55CA67D, UPC 810103472808.
The Bottom Line
The CMMG Pistol Tube Assembly (55CA67D) is the smart, straightforward way to finish or upgrade your AR pistol. With a robust black receiver extension and included ambidextrous sling end plate, you get reliability, clean ergonomics, and real-world handling improvements—right out of the box.
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