CMMG Mk3 Customizable Lower Receiver Parts Kit LR-308

CMMG Mk3 Customizable LR-308 Lower Receiver Parts Kit - Premium Build Components

CMMG
SKU:
115661798
|
UPC:
815835015415
|
MPN:
38CA61A
$41.74
$49.95
(You save $8.21 )
Current Stock:
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Product Specifications
Firearm Group:
AR Platform
Firearm Make Fit:
CMMG
Caliber-Gauge:
308 Winchester/7.62x51 NATO
Material:
Various
Product Overview

Building an LR-308 rifle from the ground up demands a complete lower receiver parts kit engineered for .308 compatibility, and the CMMG Mk3 Customizable LR-308 Lower Receiver Parts Kit delivers exactly that. Whether you're assembling your first .308 AR platform or completing a precision rifle build, this premium parts collection gives you every component you need to finish a functioning lower receiver without the hassle of sourcing pieces individually. CMMG engineered this kit specifically for LR-308 dimensions and function, so you get proper takedown and pivot pins, an improved bolt catch, and hardware sized right for the larger .308 platform.

Builders who value quality control and compatibility will appreciate that this kit accounts for .308 specifics that AR-15 kits simply don't address. The bolt catch screw, for instance, replaces the AR-15 pin design—a detail that matters when you're working with a different platform. That kind of attention reduces guesswork and potential fitment headaches on the bench. CMMG includes redundancy where it counts: dual takedown pin detents and springs, dual hammer and trigger pins, and a full complement of springs and retainers so you don't wind up hunting for oddball parts mid-build.

This is the right choice for .308 AR builders who want a complete, purpose-built solution from a maker known for AR platform expertise. You get the trigger group hardware, safety selector, magazine catch assembly, and bolt catch components all in one box—everything short of the receiver itself. It's the kind of kit that rewards you for paying attention to platform-specific engineering rather than trying to adapt universal parts to a specialized application.

Key Features

  • LR-308 takedown and pivot pins engineered for .308 platform compatibility
  • Improved bolt catch assembly with .308-specific bolt catch screw design
  • Complete lower receiver parts collection in one kit
  • Includes dual takedown pin detents and springs for reliable function
  • Full trigger group, safety selector, and magazine catch hardware
  • Buffer retainer and spring included for assembly completion
  • Purpose-built for LR-308 builds—not adapted from AR-15 specs

Specifications

PlatformLR-308 (.308)
IncludesTakedown pin, receiver pivot pin, takedown pin detents (qty. 2), takedown pin detent springs (qty. 2), hammer and trigger pins (qty. 2), safety selector, selector detent, magazine catch, magazine catch spring, magazine release button, bolt catch, bolt catch plunger, bolt catch spring, bolt catch spring pin, buffer retainer, buffer retainer spring
Bolt Catch HardwareLR-308 bolt catch screw (not AR-15 pin)

Frequently Asked Questions

Will this work on an AR-15 lower receiver?

No. This kit is specifically engineered for LR-308 platform dimensions and function. AR-15 lowers require AR-15 parts kits; using .308 components on an AR-15 platform will result in poor fitment and function.

What doesn't come in this kit that I'll need to complete a lower receiver?

This kit includes all the small parts and hardware needed for the trigger group, safety, magazine catch, bolt catch, and buffer assembly. You'll still need to source the actual lower receiver, stock assembly, and pistol grip separately.

Is this kit suitable for a first-time .308 AR builder?

Yes. Having all the LR-308-specific parts in one kit removes the guesswork of sourcing compatible components. Just make sure you pair it with an LR-308 lower receiver and follow proper assembly procedures for a .308 platform.