The Prepper Insider is reader-supported. When you buy through links on our site, we may earn an affiliate commission.
When building an AR-15 from scratch, the best way to get a functioning frame with all the right odds and ends is to invest in a quality AR-15 lower parts kit.
Let’s take a closer look at what comes in typical lower parts kits and go over some product recommendations to get started on your new build.
At a Glance: Our Top Picks for Best AR-15 Lower Parts Kits
- OUR TOP PICK: Aero Precision M4E1 Magpul MOE Lower Parts Kit
- RUNNER-UP: Bravo Company Gunfighter AR-15 Enhanced Lower Parts
- BEST BUDGET OPTION: Strike Industries AR Enhanced Lower Receiver Parts
Comparison of the Best Lower Parts Kits
| IMAGE | PRODUCT | |
|---|---|---|
Our Top Pick  |
| View Latest Price → |
 |
| View Latest Price → |
Best Budget Option  |
| View Latest Price → |
 |
| View Latest Price → |
 |
| View Latest Price → |
Are All AR-15 Lower Parts Kits The Same?
The answer is no. You will find that some kits are more comprehensive than others. Kits can also differ in the following areas.
Quality
An AR-15 lower parts kit comes with several small moving parts that play a crucial role in your build. Look for an AR-15 lower parts kit from a reputable manufacturer. You will get parts that fit properly as well as parts with durable construction.
Trigger
The trigger is a part that can vary a lot from one kit to another. The feel, weight, and shape of the trigger will differ. You can also choose between a single-stage and two-stage trigger.
Pistol Grip
The design of the pistol grip will differ from one kit to another. You can find pistol grips with a hard or rubberized finish or features like finger grooves and palm swells that make the grip more ergonomic.
What Are the Components of an AR-15 Lower Parts Kit?
The exact composition can vary from one kit to another, but most kits will include the following parts.
Pistol Grip
You can find kits that include a pistol grip, but it’s a part that’s easy to replace for a more customized build.
Trigger
AR-15 lower parts kits typically include a trigger, disconnector and pin, trigger spring, trigger pin, hammer spring and pin, and a trigger guard assembly.
Magazine Catch
The magazine catch, button, and spring will secure a magazine to the receiver.
Bolt Catch
Your AR-15 lower parts kits will include a bolt catch, spring, plunger, and roll pin.
Takedown Pins
You will also get front and rear takedown pins with matching detents and springs to connect the lower and upper receivers.
Review of the Best Lower Parts Kits
The following AR-15 lower parts kits provide you with all the parts you need to create a reliable base for your build.
Best Overall:
Aero Precision M4E1 Magpul MOE Lower Parts Kit
Pros
Cons
What Recent Buyers Report
This kit has received positive reviews because of the excellent fit and simple installation process. People say it’s easy to find instructions online and put the kit together without using a hammer. Reviews often mention the Magpul grip that comes in the kit.
Why it Stands Out to Us
Aero Precision is a reliable manufacturer. You can expect durable parts that stand out thanks to the quality of their craftsmanship.
The kit includes a MOE grip available in two finishes. The texture and comfortable design of this grip will enhance your build.
The only thing missing from this kit is a trigger. It’s a great option if you want to save money by getting a kit without a trigger so you can customize your build with the trigger of your choice.
This kit is for the Magpul Aero Precision M4E1 lower receiver, but you can use it with any similar mil-spec lower receiver.
Bottom Line
This lower parts kit from Aero Precision is an excellent mix of value and quality. We like the Magpul MOE grip, and you will get takedown pins, a bolt catch, magazine catch, a buffer retainer, a safety, and all the parts needed to install them at a great price.
Runner-up:
Bravo Company Gunfighter AR-15 Enhanced Lower Parts
Pros
Cons
What Recent Buyers Report
This kit has received a large number of positive reviews. Buyers like the smooth and crisp feel of the trigger. Reviews often mention the user-friendly installation process with the packaging that clearly labels the different parts.
Why it Stands Out to Us
This comprehensive kit comes with 27 parts. It’s a great base for a new AR-15 build. It includes a trigger assembly, trigger guard, hammer, pistol grip, bolt catch, buffer retainer, magazine catch, takedown pins, safety, and all the small parts you will need during the installation process.
The grip is a BCM Pistol Grip Mod 3. It’s a wide and ergonomic grip with a water-resistant storage compartment.
The BCP PNT trigger is easy to install. It feels smooth and crisp, and it’s a great option if you don’t have a specific upgraded trigger in mind for your build. The manufacturer uses nickel to reduce creep and get a smooth trigger pull. The manufacturing process also includes polishing the trigger to reduce friction.
Bottom Line
This lower parts kit is a must-have if you are starting a new build from scratch and need a trigger. This kit stands out thanks to the quality of the parts, especially the pistol grip and trigger.
Best for the Money:
Strike Industries AR Enhanced Lower Receiver Parts
Pros
Cons
What Recent Buyers Report
Buyers often say they picked this kit because of the value. They like the trigger and finish of the parts. Some reviewers don’t like the bolt catch and release lever because these parts stick out too far from the frame.
Why it Stands Out to Us
This kit from Strike Industries is one of the best options available if you’re shopping on a budget. It’s an affordable way to build a functional frame for your new AR-15. You can also use it as a spare parts kit if you want to have a few essential parts on hand for repairs and replacements.
The only thing missing from this kit is a pistol grip. Omitting the pistol grip is a smart choice since it’s a part that most rifle owners want to customize.
The trigger feels crisp and delivers between 4.5 and 5.5 lbs of pull. The manufacturer uses a phosphate treatment to improve the durability of the fire control group and make it resistant to corrosion.
The enhanced bolt catch design is a noteworthy feature. The bolt catch has unique angles and grip surfaces to make it more reliable.
Bottom Line
We recommend this affordable kit because of the attention to detail and quality. You will get long-lasting parts at a good price, and the trigger adds even more value to this kit.
Best AR-15 Lower Parts Kit With Stock:
Palmetto State Armory Magpul MOE Lower Build Kit
Pros
Cons
What Recent Buyers Report
Buyers like the quality of the parts and their black finish. They also like the value of the kit and how comprehensive it is. Some buyers say that the bolt catch can be a tight fit, but no other issues appear in reviews.
Why it Stands Out to Us
If you want to save time and money on your AR-15 build, you can’t go wrong with this comprehensive kit. It comes with mil-spec parts, so you can easily find other matching parts to complete your build.
You can use this kit to create a classic AR-15 build since it includes a MOE stock, MOE grip, MOE buffer tube, and MOE trigger guard. You will also get all the smaller parts you need to complete the lower receiver build.
Bottom Line
This kit is an excellent value with the MOE buffer tube, stock, grip, and trigger guard. Getting these parts in a kit limits your options for customizing your AR-15 build, but this comprehensive kit will help you save time and money if you’re after a classic AR-15 look.
Best AR-15 Lower Parts Kit Without Trigger:
CMMG Inc MK3 Lower Parts Kit
Pros
Cons
What Recent Buyers Report
Buyers like being able to choose between different shopping options. Many positive reviews mention the quality of the parts and the color-coded packaging. The only drawback mentioned by buyers is that the magazine release button is a little short.
Why it Stands Out to Us
This kit delivers an excellent value. There are three shopping options available. The most affordable kit comes with takedown pins, a safety selector, bolt catch, magazine catch, hammer and trigger pin, buffer retainer, and all the small parts you need to complete your lower receiver build.
You can choose to order the kit with a grip or with a grip and trigger if you want to spend more. Ordering the basic kit helps you save money and gives you the possibility to customize your build further by choosing the trigger and grip yourself.
The color-coded packaging is a smart feature that helps you keep track of all the different parts during the building process.
Bottom Line
We recommend this AR-15 lower parts kit from CMMG because of the quality of the parts and the durable black finish. The fit is great, and you will get all the parts you need to build your lower receiver on a budget.
Why Did These Lower Parts Kit Make Our List?
We selected these lower parts kits because of their value and quality. Here is what we took into consideration when selecting these products.
Quality
We believe the kits listed above are excellent investments. They come with durable parts you won’t have to replace anytime soon.
Quality matters when choosing a lower parts kit because parts like the trigger and safety are crucial for a firearm that is safe to operate and parts like the takedown pins maintain the integrity of your frame.
Fit and Assembly
Proper fit is often the mark of quality craftsmanship. You shouldn’t struggle when assembling different parts and shouldn’t run into issues with rattling or wobbling when using your firearm.
Fit is important for safety reasons, and it makes the receiver easier to assemble and take apart for cleaning or upgrading your build in the future.
Components
We looked for comprehensive kits so you can get most of the parts you need to build your AR-15 frame. It can be expensive and time-consuming to track down all the small pins and springs you need otherwise.
We also included some diversity in the component selection because every build is unique, and you might want to customize parts like your trigger, pistol grip, or buffer tube instead of using the parts that come in a kit.
How to Install AR-15 Lower Parts Kit
You can install an AR-15 lower parts kit with a few simple tools. Here’s what you will need:
- Punches to create holes for the pins if needed
- Needle-nose pliers
- Boxcutter
- Hammer
Here are the steps to follow:
- Start with the magazine catch. Insert it on the left-hand side of the receiver, insert the spring, and the button on the other side. Use a magazine to test it.
- Install the trigger guard next. Attach the detent on it and push it into the receiver. Secure it by adding the roll pin for the back end of the trigger guard.
- You can now install the bolt catch. Protect your receiver with some tape to avoid scratching the finish. Insert the retaining pin using the pliers and the hammer. Add the spring, the buffer, and the bolt catch. Secure the bolt catch by pushing the pin in all the way through.
- Install the front takedown pin, spring, and detent. Hold the detent down with the boxcutter to insert the pin.
- Attach the disconnector and trigger spring to the trigger. Push the trigger into the receiver and secure it with the trigger pin.
- Cock the hammer back and insert the safety in the fire position.
- You can install the selector detent spring and pistol grip next. Insert the detent spring into the receiver and push the bolt through the bottom of the pistol grip. Push the pistol grip in place and add the spring.
- Add the buffer retainer. Push the spring into the receiver, attach the buffer retainer, and screw in the buffer tube.
- Insert the rear takedown pin into the receiver. Add the detent and the spring, push the back plate to hold it in place, and finish pushing the takedown pin in.
- Tighten the castle nut, place the buffer spring and retainer inside of the buffer tube, and finish by mounting the upper and lower receiver together.
Conclusion
It’s important to consider the quality and the different parts included when choosing an AR-15 lower parts kit. We recommend the Aero Precision M4E1 Magpul MOE Lower Parts Kit because it fits most mil-spec lower receivers. This kit includes quality parts, including a MOE grip.