An AR-15 lower parts kit (LPK) holds the small parts that turn a stripped lower into a working one: pins, springs, detents, the safety selector, magazine catch and bolt catch. Some kits include the trigger group and grip; others leave them out so you can choose your own. Shop kits from CMMG, Strike Industries, Battle Arms Development and more.
Complete Kits vs Kits Without a Trigger Group
Read the kit name before you buy. A complete kit, such as the CMMG LPK 556, includes the trigger and hammer, according to its product page. Kits labeled "without grip/FCG" or "no FCG" leave out the fire-control group, and some also leave out the grip or trigger guard. Our listings include kits of this type from CMMG, TPS Arms, Spike's Tactical, CMC Triggers, Strike Industries and LBE Unlimited. Pick a trigger to pair with them using our AR-15 trigger guide.
Enhanced and Ambidextrous Kits
Enhanced kits swap in upgraded controls. The Strike Industries Enhanced Lower Parts Kit includes a Strike magazine catch and enhanced pivot and takedown pins, and the Battle Arms Development Enhanced LPK Mod3 includes BAD's enhanced bolt catch and magazine catch, according to their product pages. The Sons of Liberty Gun Works Blaster Guts B5 Ambi kit adds ambidextrous controls.
AR-15 vs AR-10 (.308) Kits
AR-15 and AR-10 (.308) lower parts kits are not interchangeable. Kits marked 308 or AR10, such as the CMMG LPK 308 and Luth-AR 308 kits, are for .308-pattern lowers. For an AR-15, choose a kit marked AR-15, 556 or 223/556.
What Else You Need
A kit finishes the receiver's controls. You still need a stripped AR-15 lower, a buffer tube assembly with a stock, and an AR-15 upper receiver. See the main AR-15 lower receivers guide for how the parts fit together.
Shipping
Orders of $500 or more ship free; parts orders under $500 ship for a flat $12.99. Returns are accepted within 60 days with a 15% restocking fee on undamaged items.
AR-15 Lower Parts Kit FAQ
Does a lower parts kit include a trigger?
Some do and some do not. Kits named "without FCG", "no FCG" or "without trigger group" leave out the trigger and hammer. Check the kit name and product page.
Will an AR-15 lower parts kit fit an AR-10?
No. AR-10 (.308) lowers need a kit made for them. Look for 308 or AR10 in the kit name.
Do I need special tools to install a lower parts kit?
Installation uses punches, a small hammer and a vise block or bench support. If you are unsure, have a gunsmith install it.