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AR-15 Lower Receivers

An AR-15 lower receiver forms the serialized foundation of a compatible AR-15 rifle or pistol build, supporting the fire-control group, magazine, grip, safety selector, buffer system and stock or brace. Ballistic Barn offers AR-15 lower receivers for customers building a new firearm or replacing the receiver at the center of an existing configuration.

Read More About Our AR-15 Lower Receivers

The lower receiver determines the platform and provides the mounting points for the lower-parts kit, trigger, grip, receiver extension and related controls. Selecting a properly manufactured lower helps provide dependable fitment with compatible AR-15 upper receivers and lower components.

This category currently contains AR-15 lower receivers only. These receivers are not intended for AR-10, LR-308, SR-25 or other large-frame AR platforms, which use different receiver dimensions and component patterns.

After choosing a receiver, use the related parts links below to shop lower-parts kits, trigger upgrades, buffer-system components, stocks and pistol braces needed to complete or configure the lower assembly.

Lower receivers are regulated firearm components and must be transferred in accordance with applicable federal, state and local laws. Review the individual product listing and transfer requirements before ordering.

The Serialized Foundation of Your AR-15 Build

Choose an AR-15 Lower Receiver for Your Next Build

An AR-15 lower receiver supports the trigger, controls, magazine, grip and buffer system while joining to a compatible AR-15 upper. Select your receiver first, then use the related category links below to find the components needed to complete the lower assembly.

Shop Related AR-15 Lower Components

These categories contain the primary components commonly used to complete, configure or upgrade an AR-15 lower receiver.

Complete Your AR-15 Lower

All Lower Receiver Parts Browse the complete lower-parts category. Lower Parts & Kits LPKs, springs, pins, detents, catches and controls. Trigger Upgrades Performance fire-control options for compatible AR-15 lowers. Buffer Tube Parts & Kits Receiver extensions, buffers, springs and related components. Stocks & Pistol Braces Complete the rear of the lower with a compatible configuration. AR-15 Upper Assemblies Pair the completed lower with a compatible caliber upper.

What an AR-15 Lower Receiver Supports

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Fire-Control Group Supports the trigger, hammer, disconnector, safety selector and related pins.
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Magazine & Controls Houses the magazine catch, bolt catch, pivot pins and takedown controls.
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Buffer System Accepts the receiver extension, buffer, spring and compatible stock or brace.
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AR-15 Platform Only Not compatible with AR-10, LR-308 or SR-25-pattern upper receivers.

This Category Contains AR-15 Lower Receivers Only

AR-15 and large-frame AR lower receivers are not interchangeable. Do not attempt to pair an AR-15 lower with an AR-10, LR-308 or SR-25-pattern upper. Always verify receiver platform, caliber requirements and component compatibility before assembly.

AR-15 Lower Receiver Buying Guide

Stripped vs. Complete Lower

A stripped lower provides the serialized receiver so you can select each internal component. A complete lower may arrive with the trigger, controls, grip and buffer system already installed.

Forged vs. Billet Construction

Forged lowers are widely used and generally follow familiar AR-15 dimensions. Billet lowers may offer distinctive machining, styling or integrated features.

Lower Parts Kit Selection

Choose between a complete LPK or a kit without the fire-control group when installing an aftermarket trigger. Confirm that all controls match the receiver.

Trigger Selection

Trigger pull weight, break, reset and intended use influence the best choice. Verify compatibility with the receiver, safety selector and intended application.

Buffer System Matching

Match the receiver extension, buffer and spring to the upper's barrel length, gas system, bolt carrier group, ammunition and suppressor use.

Stock or Brace Configuration

Confirm receiver-extension dimensions and follow all applicable federal, state and local laws when selecting and configuring a stock or pistol brace.

AR-15 Lower Receiver Parts and Compatibility

Component Compatibility What to Verify
Upper Receiver Compatible AR-15 pattern Takedown-pin fit, proprietary receiver features and caliber-specific requirements.
Lower Parts Kit AR-15 specific Included fire-control group, grip, safety and receiver-specific controls.
Trigger Compatible AR-15 fire-control group Trigger-pin dimensions, safety compatibility and manufacturer approval.
Safety Selector AR-15 compatible Semi-automatic configuration, trigger compatibility and ambidextrous clearance.
Grip Standard AR-15 pattern Grip screw, selector-detent spring location and receiver contours.
Receiver Extension Rifle or carbine configuration Tube type, stock or brace fit, buffer length and intended upper configuration.
Buffer & Spring Matched to operating system Barrel length, gas system, BCG mass, ammunition and suppressor use.
Stock or Brace Matched to receiver extension Mil-spec or commercial tube dimensions and applicable law.
Magazine Caliber and lower dependent Cartridge geometry, magazine well, feeding requirements and capacity laws.

Why Buy an AR-15 Lower Receiver From Ballistic Barn?

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AR-15 Platform Focus
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Based in Fredericksburg, Texas
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Related Build Components
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Clear Compatibility Guidance

Ballistic Barn makes it easier to move from the serialized lower receiver to the parts needed to complete the build. Use the related categories above to compare lower-parts kits, triggers, buffer systems, stocks, braces and compatible AR-15 upper assemblies.

AR-15 Lower Receiver FAQs

Is an AR-15 lower receiver considered a firearm?

Yes. Under federal law, the serialized lower receiver is generally treated as the regulated firearm component and must be transferred through the required legal process. State and local requirements may also apply.

Do you currently sell AR-10 lower receivers?

No. This category currently contains AR-15 lower receivers only. AR-10, LR-308 and SR-25-pattern lowers use different dimensions and are not represented in this category.

Will an AR-15 lower fit any AR-15 upper?

Most standard-dimension AR-15 lowers are designed to mate with compatible AR-15 upper receivers, but manufacturer tolerances, proprietary designs and caliber-specific requirements should always be checked.

What parts are needed to complete an AR-15 lower receiver?

A typical lower build requires a lower-parts kit, trigger or fire-control group, safety selector, magazine catch, bolt catch, pivot and takedown pins, grip, receiver extension or buffer tube, buffer, spring and stock or brace where lawful.

What is the difference between a stripped and complete lower receiver?

A stripped lower is generally the serialized receiver without the lower-parts kit, trigger, grip or buffer system installed. A complete lower includes some or all of those components, depending on the product listing.

Are forged and billet AR-15 lowers interchangeable?

Both can be compatible with standard AR-15 components when manufactured to compatible dimensions. Billet lowers may include styling or proprietary features, so the individual receiver specifications should be reviewed.

Can I use a standard AR-15 trigger in these lowers?

Most standard AR-15 lower receivers accept compatible AR-15 fire-control groups, including many aftermarket triggers. Always confirm the trigger manufacturer's receiver and safety requirements.

What buffer system should I use with an AR-15 lower?

The correct buffer tube, buffer and spring depend on the upper configuration, gas system, barrel length, bolt carrier group, ammunition and whether the firearm is suppressed.

Can an AR-15 lower be used with different calibers?

Yes, many cartridges can be used with a compatible AR-15 lower by installing the correct upper, bolt, magazine and operating components. Calibers requiring a large-frame receiver cannot be used on an AR-15 lower.

Does an AR-15 lower receiver need to ship to an FFL?

Generally, yes. Serialized lower receivers are regulated firearm components and normally must be shipped to a properly licensed dealer for transfer unless a specific lawful exception applies.

Can I install the lower-parts kit myself?

Many owners assemble AR-15 lowers with the proper tools and knowledge, but correct installation and safe function are essential. Work beyond your experience should be completed or inspected by a qualified gunsmith.

Why buy an AR-15 lower receiver from Ballistic Barn?

Ballistic Barn focuses on compatible parts, clear product information and practical support for customers completing AR-15 builds. Related lower parts, trigger and buffer-system categories make it easier to source the remaining components.

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