The Best AR-15 Lower Parts Kit – Rated and Reviewed

Feature image AR-15 Lower Parts Kit

Being able to build your own AR-15 can bring you many benefits. You will be able to customize your AR-15 with the parts that you prefer. Besides that, buying individual parts of your AR-15 and putting them together allows you to understand your AR-15 better. At the same time, if you are able to find good quality products at a cheap price, building your own AR-15 can save you a lot of money. 

It can be a lot of fun building your own AR-15, handpicking each individual part and putting them together piece by piece. However, it will take you way too much time to find each individual parts in the market. This is where the AR-15 lower parts kit comes in. 

An AR-15 has parts that are essential for you to construct your own AR-15 and saving you the trouble to look for each of the parts individually. A good AR-15 lower parts kit should include everything that you need to modify the lower pieces of your AR-15.

In this review, we will be looking at some of the best AR-15 lower parts kits in the market. But before that, let’s have a look at what should be included in a lower parts kit for you to completely assemble the lower of your AR-15.

The Parts in a Lower Parts Kit

Trigger, Trigger Spring, Trigger Pin, Trigger Guard Assembly, Hammer, Hammer Spring, Hammer Pin, Bolt Catch, Bolt Catch Spring, Bolt Catch Roll Pin, Bolt Catch Plunger, Disconnector, Disconnector Spring, Safety Selector, Safety Selector Detent, Safety Selector Detent Spring, 2 Takedown Detents and Springs, Rear Takedown Pin, Pivot Pin, Buffer Retainer and Spring, Magazine Catch Assembly, Pistol Grip.

Best AR-15 Lower Parts Kit – Reviewed

With a better insight of what should be included in a lower parts kit, now let’s look at what are the available options in the market. 

1. Bravo Company Gunfighter AR-15 Enhanced Lower Parts Kit

The Bravo Company Gunfighter AR-15 Enhanced Lower Parts Kit is the lower parts kit that you would normally get on most of the Bravo Company rifles. This AR-15 lower parts kit does not include a stock. The trade-offs for not having a stock is the additional pistol grip and trigger. 

The parts that are included in this kit is good enough to put together a complete and upgraded AR-15. This kit may be a little pricier than some of the lower parts kits in the market, but it will be worth your money. The reason for that is because the kit includes parts that are necessary for the upgrade of your AR-15.

The remarkable parts in the Bravo Company Gunfighter AR-15 Enhanced Lower parts Kit have to be the enhanced trigger guard. Its standards are beyond a normal trigger guard. The trigger guard is curved and therefore letting you access your trigger better. 

Other parts of this kit that makes it worth your money is the safety selector. The safety selector is tight and crisp and not too hard that you have to put in a lot of effort to flip it. This ensures that your safety will not be accidentally engaged or disengaged. 

The price that you are paying for this AR-15 lower parts kit is not just for the enhanced parts but the quality of them too. The parts that are included in this kit are designed to be long-lasting and are constructed to meet military standards. 

Parts

BCM PNT Hammer, Hammer Spring, BCM PNT Trigger, Trigger Spring, Hammer/Trigger Pins, Disconnector, Disconnector Spring, Bolt Catch, Bolt Catch Plunger, Bolt Catch Spring, Bolt Stop Pin, Rear Pivot Pin, Buffer Retainer, Buffer Retainer Spring, Magazine Catch Button, Magazine Catch Spring, Magazine Catch, Rear Take Down Pin, Selector (Safety), Selector Detent, Selector Detent Spring, BCM Enhanced Trigger Guard, BCM Trigger Guard Pin, BCM Trigger Guard Screw, BCM Pistol Grip Mod 3, Grip Screw, Locking Washer, Take Down/ Pivot Pin Detent, Take Down/ Pivot Pin Detent Spring.

Pros

  • Include parts that are not commonly found in other lower parts kits – An enhanced trigger guard and pistol grip that some kits do not have.
  • Easy to install – The lower parts kit package comes with labelled pictures for you to follow and assemble the parts. 
  • Mil-spec parts – parts are built according to military specifications and some are built with better quality. 

Cons

  • Pricey – Above average market price for an AR-15 lower parts kit.

2. CMMG AR-15 Gunbuilder’s Lower Build Kit

The CMMG AR-15 Gunbuilder’s Lower Parts Kit is a lower parts kit that has the parts that are required to complete an AR-15 lower receiver. Trigger, grip and trigger guard are not included in this kit. These parts are not included in the CMMG AR-15 Gunbuilder’s Lower Parts Kit as they are common parts that people upgrade. 

This kit is mainly meant for repairing or replacing your AR-15 parts. It lacks some parts like the trigger, grip and trigger guard which is why it will cost lesser. The CMMG AR-15 Gunbuilder’s Lower Parts Kit allows you to get parts such as pins and bolt catches for a low price. 

If you are looking to fully construct an AR-15, this kit will not be recommended since this lower parts kit lacks some of the key components. However, if you are looking to repair or replace parts of your AR-15, this kit will be a great choice for you. 

Even though the CMMG AR-15 Gunbuilder’s Lower Parts Kit may be a cheap kit, it can be assured that the quality of the parts in this kit is ideal. Components of this kit are of military standards or even better. 

The safety selector of the CMMG AR-15 Gunbuilder’s Lower Parts Kit is a good example of a part that is better than most military standards safety selectors. The safety selector is able to click into position smoothly without any obstruction. This ensures that your AR-15 does not fire on accident.  
This kit can be put together very easily, here’s a simple video of steps to put the CMMG AR-15 Gunbuilder’s Lower Parts Kit together.


Parts

Takedown pin, Receiver pivot pin, Takedown pin detent (2), Hammer and trigger pin (2), Safety selector, Selector detent, Magazine catch, Takedown pin detent spring (2) magazine catch spring, Magazine release button, Bolt catch, Bolt catch plunger, Bolt catch spring, Bolt catch spring pin, Buffer retainer, Buffer retainer spring

Pros

  • Good quality – Mil-spec or better standard of parts.
  • Durable – Good quality parts ensuring that your AR-15 will last long
  • Good kit for repairing works – Has all the parts required to repair or replace parts of your AR-15 lower receiver. 
  • Easy to install – A detailed video showing you how to install each component of the kit. 

Cons

  • No trigger, grip or trigger guard – Does not include parts like the trigger, grip or trigger guard for upgrading.

3. Aero Precision AR-15 Standard Lower Parts Kit

The Aero Precision AR-15 Standard Lower Parts Kit is a very standard AR-15 lower parts kit with all the components that are necessary. Its price range is towards the lower end but the quality of this kit is definitely not.

Even though it is just a typical AR-15 lower parts kit, the parts are better quality than other standard lower parts kit. Once you get ahold of this kit, you will realise that the finish of the parts in this kit are smoother compared to the parts in other kits. 

The parts that are in the Aero Precision A-R15 Standard Lower Parts Kit are constructed to match military specifications. However, the quality of the parts does not feel like Mil-Spec at all, it feels better. For instance, the trigger that is in this kit is phenomenal, it is light and smooth and you will definitely put a smile on your face when you are firing it. 

When it comes to the installation of this kit, it can be done easily and all the parts will fit perfectly. The Aero Precision AR15 Standard Lower Parts Kit is a good kit if you are looking to upgrade your trigger and some other parts of your AR-15. You pay a standard price for this kit and get a good trigger out of it. 

Parts

Takedown/pivot Spring, Takedown/pivot detent, Trigger/hammer pin, Takedown pin, Pivot pin, Bolt Catch, Bolt Catch Spring, Bolt Catch buffer, Bolt catch roll pin, Safety Selector, Safety Selector spring, Safety Selector detent, 4-40 Set Screw (for threaded takedown pin detent hole), Buffer retainer, Buffer retainer spring, Trigger guard, Trigger guard roll pin, A2 pistol grip, Pistol grip screw, Pistol grip lock washer, Trigger spring, Hammer spring, Disconnector spring, Magazine catch body, Magazine catch spring, Magazine catch button, Hammer, Trigger, Disconnector.

Pros

  • Good trigger – Smooth and no creep trigger, can be a good upgrade for your AR-15. 
  • Mil-Spec – Constructed according to military specifications, parts will fit perfectly.
  • Better than average quality – Quality is better than other Mil-Spec AR-15 lower parts kit. 

Cons

  • Some parts are not as durable – Only a standard lower parts kit, quality not the best in the market so some parts may not last as long.
  • Very normal – Not desirable for shooters that are building a not-so-ordinary AR-15.

4. Brownells MOE AR-15 Lower Parts Kit

The Brownells MOE AR-15 Lower Parts Kit is a very high end lower parts kit that includes parts not normally seen in a standard AR-15 lower parts kit. The kit has a buffer assembly, a choice between the Geissele 2 Stage Enhanced Trigger or the Geissele Rapid Fire Trigger. Those parts are what most lower parts kit have which is why it is more expensive than a standard AR-15 lower parts kit. 

The price that you are paying is not just for the parts that are included, it is also for the convenience. The Brownells MOE AR-15 Lower Parts Kit is a very complete kit with all the necessary parts that you need to upgrade or repair your AR-15. That extra money that you pay saves you the time looking for any individual parts for your AR-15.

Besides that, it is also a good AR-15 lower parts kit for beginners. Everything is included inside and a beginner can spend more time learning about how to build the AR-15 rather than spending the time looking for the best possible parts. 

Brownells is a reputable retailer of gun parts and accessories, just like this Brownells MOE AR-15 Lower Parts Kit, you will be getting the best quality of parts that are available in the market. 

The two triggers that you can choose from the Brownells MOE AR-15 Lower Parts Kit are the Geissele 2 Stage Enhanced Trigger or the Geissele Rapid Fire Trigger. The Geissele 2 Stage Enhanced Trigger is light and smooth and ideal for precision shooting where accuracy and reliability are important. On the other hand, the Geissele Rapid Fire Trigger is a smooth trigger designed for rapid shooting. 

Parts

Geissele 2 Stage Enhanced Trigger/Geissele Rapid Fire Trigger, A2 pistol grip, Screw and washer, Bolt catch, Plunger, Roll pin and spring, Magazine catch, Button and spring, Selector, Detent and spring, Front pivot pin, Rear takedown pin, (2) takedown detents and springs, Buffer retainer and spring, Trigger guard and roll pin.

Pros

  • Complete kit – Most complete kit in the market that includes choices of triggers and a buffer assembly that most standard kits do not have.
  • Beginner-friendly – All the necessary parts are available in the kit, beginners do not have to spend time looking for the best possible parts. 
  • Good quality – Paying at a premium price for parts that are better than Mil-Spec quality and sold by a reputable retailer. 
  • Choice of two good triggers – Both choices of triggers are of high quality and manufactured by a well-known company, Geissele Automatics.

Cons

  • Pricey – Above average price for an AR-15 lower parts kit. 
  • Includes A2 pistol grip – Not the most comfortable pistol grip in the market.

5. Geissele Automatics AR-15 Lower Build Kit

Geissele Automatics is famous for the gun parts that they manufacture, parts like triggers, handguards and muzzle devices. They are also known for producing good parts just like the Geissele Automatics AR-15 Lower Parts Kit. 

The Geissele Automatics AR-15 Lower Parts Kit is a complete kit with all the necessary parts in an AR-15 lower parts kit. However, the kit does not include a pistol grip and trigger guard. It may not be such a bad thing that those parts are not included in this kit, those parts are very depending on the shooter’s preference so you can buy those parts separately and put it together with this kit.

Geissele Automatics are well-known because of the outstanding and carefully designed products. The Geissele Automatics AR-15 Lower Parts Kit is no exception. Parts in this kit are of high-quality and are made to military specifications, this means the parts will fit together perfectly. 

Parts

Bolt catch, Bolt catch plunger / spring / roll pin, Mag release, Mag release button, Mag release spring, Buffer retainer spring, Safety, Buffer retainer, Safety detent & spring, Trigger guard & roll pin, Takedown detents & springs, Pivot/takedown pins

Pros

  • Good quality – Made by a reputable company, Geissele Automatics, and well-known for its high-end quality product.
  • Complete kit – Has every part required for an AR-15 lower parts kit except for pistol grip and trigger guard.
  • Customizable – Allows you to choose your preferred pistol grip and trigger guard for maximum satisfaction.
  • Mil-Spec – Constructed to meet military specifications, parts fit perfectly. 

Cons

  • No pistol grip and trigger guard – Can be troublesome to find the perfect pistol grip and trigger guard.

Final Verdict

If you are new to building your own AR-15, kits like the Brownells MOE AR-15 Lower Parts Kit will be a great choice as it has everything you will need and can be put together easily. The CMMG AR-15 Gunbuilder’s Lower Parts Kit is also a great choice for beginners and its at a cheaper price compared to the Brownells MOE AR-15 Lower Parts Kit but only some parts excluded. 

For shooters who prefer to have customized pistol grips and trigger guard, the Geissele Automatics AR-15 Lower Parts Kit is recommended. The Aero Precision AR-15 Standard Lower Parts Kit or the Bravo Company Gunfighter AR-15 Enhanced Lower Parts Kit can be a good choice if you are looking to replace some parts of your AR-15 and getting an upgrade for your trigger. 

Overall, the best AR-15 lower parts kit will be the Brownells MOE AR-15 Lower Parts Kit as it has all the parts necessary and also choices of two good-quality triggers. It may be more expensive but it is definitely worth your money. 

Frequently Asked Question 

Q: Does lower parts kit matter?

A: Yes. A good fit and finish of parts do matter, the parts of a lower parts kit will work but sometimes some work may need to be done for a smoother function.

Q: Is it hard to build an AR-15?

A: Yes. If you are not a mechanically-inclined person, building an AR-15 can be challenging. However, the more mistakes you make, the experience you gain and building an AR-15 can get easier and save you some money in the future. 

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