5 Best Lower Parts Kit AR15

Most experienced tactical AR15 shooter would eventually build their own rifle to exactly the way they want it. The AR15 lower parts kit (LPK) are readily available. Here, I've curated a list of the top 5 AR15 LPKs that can help you complete your AR15 lower receiver builds. 

There are standard kits, and there are fancier ones such as Radian. 

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Palmetto State Armory MOE Lower Build Kit: Best Overall

The Lower Parts Kit from Palmetto State Armory (PSA) is a comprehensive package designed to ensure a smooth assembly of your lower receiver. This kit comprises top-quality items from leading brands, including the Mil-Spec MOE Stock and MOE grip from Magpul Industries and a sturdy Mil-Spec buffer tube assembly.

All components in the kit are meticulously crafted in the USA, guaranteeing exceptional performance and unmatched quality. One left-handed shooter found the kit flexible enough to accommodate an ambi safety switch. While the kit might not include top-tier upgrades, users have found it to offer solid value for money, with parts of known and proven quality.

If you're looking for an all-inclusive, budget-friendly kit with some decent upgrades, customers agree that this kit from PSA fits the bill nicely.

Geissele Ultra Duty Lower Parts Kit: Best Durability

The Geissele Ultra Duty Lower Parts Kit, designed with top-tier components to enhance the longevity of your weapon beyond what standard parts offer. Key elements of this kit are crafted from stainless steel for rust resistance and durability in the most challenging conditions.

The Geissele CP-05-435 Ultra Duty Lower Parts Kit includes an Ambidextrous Super Configurable Safety, providing tactile feedback when switching between safe or fire mode.

The package also contains the famed Maritime Bolt Catch, complete with aggressive texturing and extended paddles for effortless grip. This kit is your trusted companion for constructing or refurbishing your firearm's lower receiver.

Many customers vouch for the quality and reliability of this kit, noting its worth for those prioritizing a higher-end build. The components are reported to install smoothly and function impeccably. Some customers also appreciate the ambidextrous selector, with one customer stating they can no longer do without it after using it for the first time.

Radian Weapons Lower Parts Kit - High End

Radian Weapons make top notch high end accessories for AR15 rifles. Many key components however are sold separately including the Talon 45 / 90 safety lever. Their most popular lower parts are:

CMC Lower Parts Kit: Exceptional Trigger

CMC is known for their excellent drop-in AR15 triggers. Their Single Stage, Small Pin, 3.5lb pull trigger lower parts kit, excluding the grip, is recommended for builders who want a basic lower parts kit with an outstanding trigger right out of the box.

Aero Precision M5 Lower Parts Kit: Popular Choice

The M5 Lower Parts Kit, tailored for the Aero Precision M5 Lower Receiver, includes all necessary components and a Magpul MOE® Grip. The M5-specific parts include the M5 Takedown Pin, M5 Pivot Pin, M5 Bolt Catch, and Extended Magazine Catch Button.

The Magpul grip is highly appreciated, as are the extra springs provided in the kit.

The sealable grip compartment is a standout feature, enhancing the kit's value for any build. Customers laud the ergonomics, citing it as top-notch. The fit and finish have received praise for being very good, with no slop or gaps noticed anywhere.

ALG Defense Lower Parts Kit: Advanced Combat Trigger

The ALG Defense LPK includes all the parts required to finish a lower receiver build. The ACT (Advanced Combat Trigger) is smoother and sharper than a stock trigger. The sear geometry remains unchanged from the standard profile, maintaining the high reliability that the stock trigger is known for. The trigger and hammer are made from true 8620 alloy steel military specification castings, correctly carburized, quenched, and tempered for high surface hardness.

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