What is the best ar-15 lower parts kit

What is the best AR-15 lower parts kit?

We get asked frequently “what the best AR-15 lower parts kit is” or “who makes the best AR-15 lower parts kit”. In fact, we get the question so often that we decided to write a post about it in hopes that it will help answer the question for you. We’ll cover the criteria to determine the best lower parts kit, the various brands that make them, and the differences between lower parts kits and even between brands.

Criteria for Finding the Best Lower Parts Kit

The first thing we need to look at is determining the criteria we’ll use to determine the best lower parts kit and the best brand. Keep in mind that we can’t just compare two lower parts kits to each other without making sure that they contain the same parts. That’s why we begin with the type of lower parts kit.

Lower Parts Kit Types

It would be easy to think that there is just one type of kit that fits all AR-15 and provides the same functionality. That simply isn’t the case so we need to look at a variety of LPKs (lower parts kits) and the purpose of each.

Standard Lower Parts Kit

The standard LPK is what the majority of people are asking about when they ask who makes the best lower parts kit or what is the best lower parts kit. This kit contains everything you need to turn your 80% lower or 100% lower into a functioning lower. It includes all the necessary components like springs, pins, the fire control group including the trigger, hammer, safety selector, takedown pin, pivot pin, as well as the detents needed. If you are building an AR-15 lower receiver or completely replacing the lower parts kit, this is one of the kits you need to consider.

Enhanced Lower Parts Kit

This is where we see confusion start to come in. A lot of times it’s difficult to know what the differences between a standard lower parts kit and an enhanced lower parts kit are. An enhanced lower parts kit is typically a standard LPK with an upgraded component such as the trigger group. Sometimes a manufacturer will include coated springs as well but more often than not you’ll find a better AR-15 trigger and trigger guard and all other parts are standard. This is usually the easiest way to “enhance” a lower parts kit.

Drop-In Lower Parts Kit

A drop-in lower parts kit is a kit designed for those that are using a drop-in trigger. A drop-in trigger is a trigger, hammer, disconnector, and springs already assembled and housed together. This type of trigger is easier to install but, in regards to a drop-in lower parts kit, may or may not be included. Aside from the fire control group, every other part you need to install is included in a drop-in lower parts kit. Keep in mind that drop-in kits do come in standard and enhanced versions with, again, the differences being things like black oxide springs, better trigger guard, and even the fire control group itself could be included in an enhanced drop-in lower parts kit.

Repair Kit

The repair kit can have many names a variations. Common names for this type of kit are field kit, GI kit, repair kit, and other similar names. A repair kit will usually contain parts like a firing pin, various springs, and even a few pins. For the purposes of comparing, we won’t compare kits at this level.

Lost Parts Kit

Similar to a repair kit, the lost parts kit will typically contain various springs and pins. The biggest difference between a repair kit and a lost parts kit is that a lost parts kit may only have springs and pins. Again, for our purposes in this comparison we won’t discuss this type of kit.

Lower Parts Kit Brands

So the big question many people ask – what brand makes the best lower parts kit? To help differentiate between quality of the parts themselves, we’ll classify each manufacturer based off their standard and enhanced kits. The classifications are as follows:

Quality Rating

T1

This class is for the highest level of quality. Each part is finished in black oxide or similar coating. The main components of the kit must be made from heat treated steel or better. Uses coiled steel spring pins. Upgraded pistol grip. Premium trigger which can include a drop-in style trigger. Lower parts kits must meet Mil-Spec standards.

T2

Most upgraded or enhanced kits fall into this category. The kit typically contains an enhanced trigger guard, upgraded pistol grip, and an enhanced trigger. Lower parts kit must meet Mil-Spec standards.

T3

Basic and standard AR-15 lower parts kits will typically fall into this category. Lower parts may be molded or forged. Only exposed parts are finished in black oxide or similar. Kits have standard A2 style pistol grips and standard aluminum trigger guard. Kit may or may not meet Mil-Spec standards.

Price Rating

P1

High price, high quality.

P2

Medium price, enhanced quality.

P3

Low price, standard quality.

Let’s discuss a few of the major brands and what the differences are between each brand.

CMMG Lower Parts Kit

CMMG is known for making AR-15s and other rifles. The have also gained popularity in recent years for making lower parts kits. The provide standard kits as well as kits with an ambidextrous safety selector. Another kit they make for the AR-15 is what they call a Gunbuilder’s Kit which provides all the lower parts needed except for the commonly upgraded parts such as the trigger guard, fire control group, and pistol grip.

The CMMG lower parts kit is Mil-Spec compatible and provides a standard kit at a decent price. While none of the parts provided are upgraded with any special coating outside what’s normal, they do provide the kit that contains an ambidextrous safety selector.

Lower Parts Kit Classification:

T3
P3

KE Arms Lower Parts Kit

Not as big or well known as some of the other brands listed, KE Arms does provide a myriad of options when it comes to AR-15 lower parts kits. They provide standard LPKs as well as enhanced and drop-in kits. Like CMMG, the standard lower parts kit is what you’d expect and, as such, as a lower price point. The enhanced lower parts kit provides an upgraded pistol grip and black oxide springs. If you’re looking to upgrade the trigger as well, KE Arms provides what they call a DMR drop-in kit which includes a drop-in trigger and the rest of the lower parts kit.

KE Arms lower parts kits, in my opinion, are a slightly better quality than most other manufacturers, especially when you start looking at enhanced kits with DMR triggers. The kits meet Mil-Spec and fit standard AR-15 builds.

Lower Parts Kit Classification:

T1
T2
T3
P1
P2
P3

Black Rain Ordinance Lower Parts Kit

Black Rain Ordinance only provides a couple options when it comes to lower parts kits – standard (they call it the GI lower parts kit) and BRO lower parts kit. The GI or standard parts kit is, again, what you’d expect in a standard kit. The quality is good for the money but doesn’t provide anything different from other manufacturers. Once you start looking at the BRO enhanced version you’ll see a completely upgraded kit including their drop-in trigger, anti-rotation pins, and Magpul MOE pistol grip. However, with this upgraded kit comes an upgraded price NOT based on the quality of all the parts but primarily from the trigger.

Lower Parts Kit Classification:

    T1
    T3
    P1
    P3

    Daniel Defense Lower Parts Kit

    Daniel Defense focuses on manufacturing a variety of AR-15 style rifles including .308s, 5.56, and .300 Blackouts. They also manufacture the various parts that fit these type of rifles. The Daniel Defense AR-15 lower parts kit is such an example and is manufactured to meet Mil-Spec standards. The overall quality of the standard Daniel Defense lower parts kit is above other manufacturers as the machining and finishing process focuses on improving parts that have “touch points”. This means that every part has a black oxide finish except for the springs and detents. With the extra attention to detail that Daniel Defense gives to making their lower parts kits, the price is a little more than most other standard parts kits. One thing to note is that the “standard” parts kit from Daniel Defense is typically equivalent to what other manufacturers call their enhanced parts kit.

    Lower Parts Kit Classification:

    T2
    P2

    DPMS Lower Parts Kit

    DPMS is another manufacturer that provides a basic standard lower parts kit. Quite honestly, there isn’t much difference between DPMS kits and kits made by CMMG. You’ll get your standard parts needed for installation but don’t expect a great trigger or pistol grip. If you’re shopping based on price then this is definitely a good choice.

    Lower Parts Kit Classification:

    T3
    P3

    DoubleStar Lower Parts Kit

    DoubleStar may be known for their AR-15 style rifles but their roots are in parts and accessories. That’s evident in the quality of the lower parts kit they manufacture. Made from 8620 steel and with major components finished in black oxide, the DoubleStar AR-15 lower parts kit provides a step up beyond the standard parts kit. Unfortunately, though, DoubleStar doesn’t provide a more mainstream, standard LPK.

    Lower Parts Kit Classification:

    T2
    P2

    Spike’s Tactical Lower Parts Kit

    Spike’s Tactical has quickly become a common name among AR-15 enthusiasts and is, more often than not, associated with quality rifles, parts and accessories. The Spike’s Tactical lower parts kits don’t disappoint. Their standard lower parts kit exceeds Mil-Spec standards and features a rounded hammer and black oxide finishing on many of the parts. The Spike’s Tactical enhanced lower parts kit is massively different and features like a Nickel Boron Battle Trigger, ambidextrous safety, billeted trigger guard, anti-rotation pins, and an Ergo grip.

    Lower Parts Kit Classification:

    T1
    T3
    P1
    P3

    CMC Triggers Lower Parts Kit

    CMC Triggers is primarily known for triggers but they also manufacture different variations of a lower parts kit. Their kits tend to be on the higher end of cost due to the inclusion of an upgraded drop-in style trigger. The kit also includes an anti-walk pin set and black oxide finish on all parts except springs and detents. While the upgraded trigger is nice there isn’t much else that stands out about the kits that CMC manufactures.

    Lower Parts Kit Classification:

    T2
    P2

    The biggest thing to keep in mind is that many of the AR-15 lower parts kit brands including ones not listed here may or may not manufacture the kits themselves. Often times the kits are made by one company and each brand puts their name on it. In this scenario, the brand will typically include something in the kit to differentiate themselves from other companies buying the same kit.

    So what’s the answer to who makes the best lower parts kit? That depends on your intent, the quality you’re looking for, and the price you’re willing to pay. If quality is a big deal then you can’t go wrong with a Spike’s Tactical or one of the other T1 brands. If price is what you’re after, CMMG, KE Arms, DPMS, and others with T3 kits are a good choice for you.

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