The CMMG Buffer Retainer Parts Kit, Fits AR-15, Black/Silver (55AFFDC, UPC 815835019727) is a simple but essential small-parts kit designed to keep your AR’s buffer system running reliably. Whether you’re finishing a new build, refreshing a worn lower, or stocking critical spares, this CMMG kit gives you a quality buffer retainer and spring in one convenient package. CMMG - AR 15 and AR 10 Builds and Parts+2Palmetto State Armory+2
Designed for Secure, Reliable Buffer Retention
In a standard AR-15–pattern rifle, the buffer retainer and spring keep the buffer and buffer spring properly captured inside the receiver extension when the upper is opened or the rifle is disassembled. The CMMG Buffer Retainer Parts Kit is built to do that job dependably, even on hard-run rifles.
According to CMMG and major retailers, the kit includes: CMMG - AR 15 and AR 10 Builds and Parts+2Palmetto State Armory+2
Together, they help:
Maintain proper buffer alignment
Prevent the buffer and spring from jumping forward when you crack the receivers open
Support consistent function during cleaning, inspection, and normal operation
It’s a tiny part with a big job—and exactly the kind of component you want from a reputable manufacturer.
Compatibility: AR-15 (Mk4) & LR-308 (Mk3) Buffer Systems
This kit is marketed as a drop-in solution for AR-15 buffer systems and is also listed as compatible with LR-308–pattern (Mk3) builds. CMMG - AR 15 and AR 10 Builds and Parts+2Palmetto State Armory+2
Compatible platforms include:
AR-15 / AR-15 Mk4 lowers in 5.56, .223, and similar calibers
LR-308 / AR-10–style Mk3 lowers using AR-style carbine or rifle buffer systems
If you’re assembling or maintaining a mil-spec style lower receiver that uses a standard buffer tube and retainer, this kit is built to fit right in.
High-Quality OEM Small Parts from CMMG
CMMG is widely known for producing premium AR-15 and AR-10 rifles, parts, and accessories, and this kit is no exception. Rifle Supply+2drummagazines.com+2
Why builders and armorers like CMMG small parts:
Consistent dimensions from lot to lot, reducing fitment surprises
Quality materials selected for durability in real-world use
Trusted OEM brand used by many builders and end-users
While some builds can get away with bargain-bin parts, critical retention components like the buffer retainer pin and spring are best sourced from a reputable name.
Black/Silver Finish – Easy to Identify & Match
Retail listings describe this CMMG kit as Black/Silver, reflecting the typical appearance of the buffer retainer and spring. Arnzen Arms+2drummagazines.com+2
Functionally it doesn’t matter, but visually, the black/silver combo makes it easy to confirm orientation and condition at a glance when you’re checking over a lower.
Perfect for Builds, Repairs & Spare Parts Kits
Because the buffer retainer and spring are small and inexpensive—but mission-critical—they’re smart items to keep on hand. Dealers and distributors highlight this kit as a great choice for: Palmetto State Armory+2OpticsPlanet+2
New AR-15 builds: ensure your lower has a high-quality retainer from day one
Replacement of worn, bent, or lost parts: especially if your rifle sees a lot of use
Bench stock / spare parts kits: toss a couple in your armorer’s box for future projects
If you work on rifles regularly, you already know—when a tiny part like a buffer retainer goes flying across the shop, having a CMMG replacement in the drawer is a lifesaver.
Simple Drop-In Installation
The CMMG Buffer Retainer Parts Kit is designed as a standard, drop-in replacement where a normal AR-style buffer retainer and spring are used. Install it during lower receiver assembly when you’re fitting the buffer tube/receiver extension, following safe, manufacturer-approved procedures for your platform.
Because this kit is made to mil-spec dimensions for AR-pattern systems, there’s no weird fitting, odd shapes, or brand-specific quirks to fight with—just a straightforward part that works. CMMG - AR 15 and AR 10 Builds and Parts+2Palmetto State Armory+2
Affordable Upgrade with Premium Performance
Multiple retailers list the CMMG 55AFFDC Buffer Retainer Parts Kit at a very accessible price point, making it a high-value upgrade over no-name parts. GearChase+3Rifle Supply+3Palmetto State Armory+3
You get:
For the cost of a cup of coffee, you can eliminate a common weak link in the lower receiver.
Key Features & Specifications – CMMG Buffer Retainer Parts Kit 55AFFDC
If you’re building, rebuilding, or just smartly stocking your AR spares, the CMMG Buffer Retainer Parts Kit, Fits AR-15, Black/Silver (55AFFDC, UPC 815835019727) is a dependable, affordable way to ensure secure buffer retention and smooth operation in your rifle.
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