Lower PartsValue Tier

CMMG

CMMG AR-15 Gunbuilder Lower Parts Kit

Core lower-receiver parts without a fire control group, trigger guard, or pistol grip.

Quick Specs

Price
$35
Weight
N/A
Brand
CMMG
Category
lower-part

Features

  • No fire control group
  • No pistol grip
  • No trigger guard
  • Color-coded clam-pack
  • Pins, springs, catches, and selector included

Where to Buy

Compare current prices and availability from retailers we work with.

Optics PlanetBest available

CMMG, Inc AR-15 Lower Reciever Parts Kit, Black, 55CA601

$44.89
In stock
13h ago
View offer
Palmetto State Armory

CMMG Gunbuilders AR-15 Lower Parts Kit - 55CA601

$35.19
Unknown
2d ago
View offer

Price History

90-day low $35.19 · at low now
$49.79$35.196/27/178/31

Compatibility Tags

family: ar-patternpart: lower-completion-kitassembly: excludes-fcgassembly: excludes-gripassembly: includes-safety-selector

Overview

CMMG's 55CA601 Gunbuilder kit supplies the small parts that finish a stripped AR-15 lower around the trigger and grip. It includes the takedown and pivot pins, bolt catch, magazine catch, safety selector, buffer retainer, and the matching springs and detents.

The fire control group, trigger guard, and pistol grip are not included. Pick those parts separately. The labeled clam-pack keeps the small components organized during assembly.

Key Features

  • Takedown and pivot pins with detents and springs
  • Bolt catch and magazine catch assemblies
  • Safety selector with detent and spring
  • Buffer retainer and spring
  • Labeled clam-pack for organized assembly
  • Standard AR-15 lower-receiver fit

Pros

  • +Does not make you pay for a trigger or grip you plan to replace
  • +Labeled packaging makes the small parts easy to identify
  • +Covers the standard catches, pins, selector, and springs
  • +Fits standard AR-15 lower receivers

Cons

  • Requires a separate fire control group
  • Requires a separate pistol grip
  • Trigger guard is not included
  • Costs more than some other small-parts-only kits

Detailed Specifications

compatibility
AR-15 / M4 platforms
pinDiameter
.154" standard (small pin)
Finish
Phosphate on steel components
Material
Steel construction per mil-spec
includesFCG
No - trigger group sold separately
includesGrip
No
includesTriggerGuard
No
safetySelector
Yes - standard selector with detent and spring
partNumber
55CA601

Compatible Platforms

+69 more

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