
Availability: In Stock
Building a custom AR-15 starts with a solid foundation, and the Luth-AR AR15 Lower Receiver Parts Builder Kit gives you exactly that—a complete set of mil-spec components to outfit a stripped lower without forcing you into a one-size-fits-all parts package. If you want to hand-pick your trigger, grip, stock, and safety but need all the small, easy-to-lose bits that tie everything together, this kit eliminates the frustration of a half-finished build stalled because you're missing a detent spring or takedown pin.
The Builder Kit philosophy is straightforward: Luth-AR handles the commodity hardware—the springs, pins, catches, and levers that are the same on virtually every mil-spec AR. You bring your own trigger group, pistol grip, buttstock or buffer system, and triggerguard, letting you optimize the parts that matter most to your shooting style and budget. It's a smarter way to source a lower build, especially on a Saturday afternoon when you don't want to hunt down a dozen separate vendors for single components.
Everything in the kit is designed to standard mil-spec dimensions, so compatibility with virtually any modern AR-15 lower receiver is not a concern. Whether you're assembling your first AR or your fifth, the straightforward installation of these components is well within reach for anyone comfortable with basic gunsmithing.
| Kit Contents | Buffer retainer & spring; safety selector lever with detent; selector/ejector spring; bolt catch with spring, plunger & roll pin; magazine catch; magazine release button (aluminum); front pivot pin; rear takedown pin; takedown/pivot pin detents (qty. 2); detent springs (qty. 2); hammer/trigger pins (qty. 2); mag catch/buttstock plunger spring |
| Specification Standard | Mil-Spec |
| Compatibility | AR-15 mil-spec lower receivers |
| Manufacturer | Luth-AR LLC |
Yes. All components in the Luth-AR Builder Kit are dimensioned to mil-spec standards, and virtually all currently available AR-15 lowers are manufactured to accept these parts without modification or fitment issues.
You'll need to source your own trigger and fire control components, pistol grip, buttstock or buffer system, and triggerguard. The Builder Kit supplies everything else required to finish a stripped lower.
Yes. All parts in the kit are standard mil-spec components, and installation is straightforward for anyone with basic gunsmithing familiarity. If you've assembled an AR-15 before, you'll have no trouble with these parts.
The kit includes the buffer retainer assembly, safety selector, bolt catch, magazine catch, all takedown and pivot pins, detents, springs, and hammer/trigger pins. Essentially, it covers all the small hardware that's easy to misplace or forget when sourcing components separately.

SKU: 115744418 • Width: 3in • Height: 1in • Depth: 4.75in • Weight: 0.19oz





Availability: In Stock
Building a custom AR-15 starts with a solid foundation, and the Luth-AR AR15 Lower Receiver Parts Builder Kit gives you exactly that—a complete set of mil-spec components to outfit a stripped lower without forcing you into a one-size-fits-all parts package. If you want to hand-pick your trigger, grip, stock, and safety but need all the small, easy-to-lose bits that tie everything together, this kit eliminates the frustration of a half-finished build stalled because you're missing a detent spring or takedown pin.
The Builder Kit philosophy is straightforward: Luth-AR handles the commodity hardware—the springs, pins, catches, and levers that are the same on virtually every mil-spec AR. You bring your own trigger group, pistol grip, buttstock or buffer system, and triggerguard, letting you optimize the parts that matter most to your shooting style and budget. It's a smarter way to source a lower build, especially on a Saturday afternoon when you don't want to hunt down a dozen separate vendors for single components.
Everything in the kit is designed to standard mil-spec dimensions, so compatibility with virtually any modern AR-15 lower receiver is not a concern. Whether you're assembling your first AR or your fifth, the straightforward installation of these components is well within reach for anyone comfortable with basic gunsmithing.
| Kit Contents | Buffer retainer & spring; safety selector lever with detent; selector/ejector spring; bolt catch with spring, plunger & roll pin; magazine catch; magazine release button (aluminum); front pivot pin; rear takedown pin; takedown/pivot pin detents (qty. 2); detent springs (qty. 2); hammer/trigger pins (qty. 2); mag catch/buttstock plunger spring |
| Specification Standard | Mil-Spec |
| Compatibility | AR-15 mil-spec lower receivers |
| Manufacturer | Luth-AR LLC |
Yes. All components in the Luth-AR Builder Kit are dimensioned to mil-spec standards, and virtually all currently available AR-15 lowers are manufactured to accept these parts without modification or fitment issues.
You'll need to source your own trigger and fire control components, pistol grip, buttstock or buffer system, and triggerguard. The Builder Kit supplies everything else required to finish a stripped lower.
Yes. All parts in the kit are standard mil-spec components, and installation is straightforward for anyone with basic gunsmithing familiarity. If you've assembled an AR-15 before, you'll have no trouble with these parts.
The kit includes the buffer retainer assembly, safety selector, bolt catch, magazine catch, all takedown and pivot pins, detents, springs, and hammer/trigger pins. Essentially, it covers all the small hardware that's easy to misplace or forget when sourcing components separately.
SKU: 115744418 • Width: 3in • Height: 1in • Depth: 4.75in • Weight: 0.19oz
