AR-15 Lower Parts Kits | Mil-Spec & Enhanced LPKs for AR Builds

Q: What’s the difference between an LPK with and without a fire control group?

LPKs without a fire control group are intended for use with drop-in trigger assemblies. Kits with FCG include the standard trigger, hammer, and disconnector.

Q: Will these parts work in an AR pistol lower?

Yes. If your lower is mil-spec, these parts will work in AR pistols, rifles, and carbines.

Q: Are enhanced lower parts kits worth the upgrade?

Enhanced LPKs provide smoother controls, improved ergonomics, and features like ambidextrous safeties and anti-walk pins, making them ideal for tactical or competitive use.

Q: What calibers are these lower parts kits compatible with?

These LPKs are compatible with AR-15 lowers in calibers such as .223, 5.56, .300 Blackout, and 6.5 Grendel, as long as the lower is mil-spec.

Q: Are these kits made in the USA?

Yes. All our AR-15 lower parts kits are American-made by reputable manufacturers known for consistent quality and performance.

AR-15 Lower Parts Kits | Mil-Spec & Enhanced LPKs for AR Builds

**Deltac 28pc AR-15 Lower Parts Kit** $32.95

**Aim Sports AR-15 Lower Parts Kit** $61.95

**Timber Creek Outdoors AR-15 Lower Parts Kit** $89.99

**ERGO AR-15 Upper & Lower Spring Replacement Kit** $14.00

**ERGO AR-15 Lower Spring Replacement Kit** $7.45

**Aero Ar15 Lower Parts Kit Moe Blk** $98.99

**Aero Ar15 Lower Parts Kit No Fcg** $35.99

**Aero Ar15 Lower Parts Kit Moe Fde** $98.99

**Armaspec Superlight Lower Parts Kit .223/5.56-Black** $76.49

**Armaspec Gun Builder’s LPK less FCG & Grip for .223/5.56** $67.49

**Armaspec Lower Parts Kit less Trigger Group & Grip for .223/5.56** $71.99

**Armaspec Superlight Lower Parts Kit for .223/5.56 – Blue** $76.49

**Armaspec Superlight Lower Parts Kit for .223/5.56 – FDE** $76.49

**Armaspec Superlight Lower Parts Kit for .223/5.56 – RED** $76.49

**BATTLEARMS 3-Piece AR15/M4/M16 Enhanced Lower Parts Kit Specifications Reviews BATTLEARM** $33.00

**Bcmgunfighter AR-15 Enhanced Lower Parts Kit** $123.07

**Daniel Defense AR-15 Lower Receiver Parts Kit – Semi-Auto** $129.76

**CMC Triggers AR-15 Lower Parts Kit Without Grip/fcg** $42.68

**Kak AR-15 Lower Parts Kit No Grip/trigger Guard** $44.99

**Kak AR-15 Lower Parts Kit Basic Ambidextrous Build Kit** $31.99

**Kak AR-15 Lower Parts Kit Basic Build Kit** $24.99

AR-15 Lower Parts Kits – Mil-Spec & Enhanced LPKs for Custom Builds

A quality AR-15 lower parts kit (LPK) is the foundation of any reliable rifle build. Whether you’re starting from a stripped lower or refreshing a tired setup, our handpicked LPKs ensure your fire control, pins, springs, and safeties all function with precision and consistency.

At Mounts Plus, we carry a wide range of AR-15 lower receiver parts from trusted names like Aero Precision, ERGO, Armaspec, CMC Triggers, BCM, and more. Choose from complete kits with fire control groups or minimalist options without triggers — ideal for builders using drop-in trigger assemblies.

🔧 What Is an AR-15 Lower Parts Kit?

An AR-15 lower parts kit includes the essential components needed to complete your lower receiver. Most LPKs contain:

Trigger, hammer, and disconnector (in full kits)
Selector, springs, detents, and pins
Bolt catch, magazine release, and buffer retainer
Takedown and pivot pins
Grip screw and trigger guard

Whether you're building a pistol, carbine, or SPR, these parts are precision-machined to mil-spec tolerances and designed for seamless function.

💡 Types of AR-15 Lower Parts Kits We Offer

🔹 Mil-Spec LPKs

Reliable, no-frills parts
Matches military dimensions
Great for all-around builds or replacement

🔹 Enhanced LPKs

Upgraded ergonomics and materials
May include anti-walk pins or ambidextrous safeties
Ideal for competition or tactical builds

🔹 LPKs Without Fire Control Group (FCG)

Designed for use with drop-in triggers like CMC, Rise, or Geissele
Lets you customize your trigger while keeping the rest of the parts uniform

🧱 Why Buy Your LPK from Mounts Plus?

✅ All parts meet or exceed mil-spec standards
✅ Multiple configurations — with or without FCG
✅ Top brands with proven reliability
✅ Fast U.S. shipping and expert support

We don’t just carry AR-15 parts — we source gear we trust in our own builds.

🔗 Related Lower Build Components

Drop-in triggers
AR pistol grips
Buffer tube kits
Safety selectors
AR-15 receiver sets

These kits are 100% compatible with standard mil-spec lowers, including builds chambered in .223, 5.56, .300 BLK, and 6.5 Grendel.

💬 FAQ

Q: What’s the difference between an LPK with and without a fire control group?
A: Kits without an FCG are made for builders who want to install a custom drop-in trigger. Kits with FCG include the trigger, hammer, and disconnector.

Q: Will these parts work in an AR pistol lower?
A: Yes. As long as your lower is mil-spec, these kits are fully compatible with AR pistols, carbines, or rifles.

Q: Are enhanced lower parts kits worth the upgrade?
A: Absolutely. Enhanced kits offer improved ergonomics, smoother controls, and options like ambidextrous safeties or anti-walk pins — ideal for tactical or competition setups.

Q: What calibers are these lower parts kits compatible with?
A: Most kits work with any AR-15 lower chambered in common calibers like .223, 5.56, .300 Blackout, and 6.5 Grendel, provided the lower is mil-spec.

Q: Are these kits made in the USA?
A: Yes. We only stock American-made LPKs from reputable manufacturers known for quality and reliability.

🛠️ Build With Confidence

Your AR-15 LPK is more than just springs and pins — it’s the heart of your lower receiver. Choose quality components that fit, function, and last through every range day or mission.

Shop now at Mounts Plus and finish your build the right way.