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AR-15 Kits Under $300

Guide to Cheap AR 15 Kits: Building Affordable Firepower

Complete AR-15 kits under $300 are easy to find. However, finding the right one that fits your personal preference is difficult.

While the AR-15 remains a popular and far-reaching rifle in the US, making your own from scratch is not uncommon for most shooters.

Most firearms enthusiasts believe that building your own from cheap AR kits is a major part of the fun, while others stick to buying a complete unit because of multiple reasons.

Whichever the case, today’s guide will highlight the most important considerations when purchasing cheap AR 15 build kits.

Let’s start.

Before You Start: Important Considerations for Building an AR-15

Since the AR-15 is so ubiquitous, and its parts are super easy to find, it’s very simple to build your own AR-15 rifle under $300.

However, if you don’t know how and which parts to work with, you won’t bring out the full potential of the rifle.

Let’s discuss the important stuff before you buy your first AR 15 build kit under 400 dollars.

Establish What You Want and Need

First things first, you need to know exactly what you’ll be expecting from your AR-15 platform, and this means considering your options.

Is it for hunting?


Or maybe a good old-fashioned fun machine ready for .22 LR plinking?

Whichever the case, it’s not about having a budget-first mindset as much as knowing which parts to buy.

Be Careful With Your Budget

A fully functional AR-15 build with cheap parts can be very difficult to pull off, especially if you don’t know what you’re doing.

You’re either gonna spend much more money with cheap AR kits or build a faulty, poor-quality AR platform that can be potentially dangerous to handle.

Whatever you do, do not underestimate your budget when an AR-15 is in question.

Most hunters start off with AR-15 build kits under $300, only to find themselves spending over a thousand dollars on unnecessary aftermarket parts or even repair costs!

Key Tools Needed for Smooth AR-15 Assembly

The tools and equipment budget is another thing to keep in mind.

Since you’re going to take the DIY route, you will need high-quality tools to help you build your platform with cheap AR 15 kits.

Essential tools will help you with the AR-15 assembly, and you will need to cut a chunk off your budget on this segment. Otherwise, going to the gunsmith will probably cost you even more.

Before you start tinkering with AR kits under 300 dollars, here are the most important tools you’ll need.


Workbenches are the main thing you will need before you start building your AR-15 rifle.

Sure, you can do it on your kitchen table or on your garage table, but having a dedicated workbench will mean a world of difference.

A good work surface is an absolute necessity, especially when you need fixed power tools, storage containers, and vise blocks.

Vise Block

You’re not going anywhere without a proper engineer’s vise block. The vise will be an absolute necessity that can help you hold your AR-15 in place while you’re tweaking it. It’s difficult to modify or assemble an AR-15 rifle without a good vise block or bench vise.


Yes, wrenches.

An AR-15 armorer’s wrench, a half-inch torque wrench, hexes, Allen, and star wrenches, among others, are the most important tools when you want to fit a barrel on your AR-15 rifle.

Moreover, tightening castle nuts and fitting muzzle devices is nearly impossible without a proper wrench.

Other Tools

While the tools we mentioned now are basically the essentials, there are other tools that will make your life easier when modding your own guns.

For example, an AR-15 steel punch set can help you with sticking roll pins. Another useful tool is a flat-head screwdriver for modding your pistol grips.

Understanding the Essential Parts for an AR-15 Build Kit

When choosing your aftermarket options to make a cheap AR-15 build kit, you need to keep in mind proper expenditure and avoid unnecessary accessories.

Expensive means quality, sure. But do you really need it?

Before you immediately go for the quality aftermarket parts, make sure you have a basic, working platform first.

Here’s a breakdown of all the cheap AR 15 build kits and parts you’ll need.

Essential Upper Receiver Parts

Barrel: In no particular order, let’s start with the barrel. When going for barrels, the best results for a budget barrel can be achieved from your classic MIL-SPEC barrels. Most people go for 16 inches. Use a stabilizing arm brace instead of a stock if you want to go for the shorter SBR territory.

Bolt carrier group: Your BCG makes sure the rifle spews bullets in a semi-automatic fashion. Always make sure it has a quality coating for extra durability, like the PVD AR-15 BCG. A rainbow-coated gas block is also a good addition to the BCG.

Charging handle: Charging handles are a necessary component of your cheap AR 15 kits because of multiple reasons. Use an ambidextrous Warhammer if you want longevity.

Dust cover: Dust covers maintain your gun’s cleanliness and protect it from debris. They’re pretty fragile, so it’s a good idea to buy it in packs.

Handguard: The handguard offers protection and serves as a platform for all your other aftermarket parts.

Stripped upper receiver: Last but definitely not least, when going for a budget AR 15 build kit under 400 dollars, always make sure to grab a stripped upper receiver.

Essential Lower Receiver Parts

For your AR-15 build kits under $300 to work properly, there are important lower receiver parts that should not be ignored.

Buffer components: The buffer parts consist of the buffer tube, buffer, and buffer spring, and they reduce recoil and make sure the AR-15 cycles the BCG properly.

Lower parts: This is where the trigger, hamer, mag release, and bolt release buttons are located.

Grips: The grips are almost always cheap but extremely necessary for your comfort and reducing recoil.

Stock: The stock or brace also provides you with a decent amount of comfort and can also help your 14.5-inch barrel avoid SBR territory.

Other Parts

Aside from these essential parts, you also have gas tubes, magazines, and sights/optics that can be excellent additions to your cheapest AR-15 kits for under $300.

Still, these generally have a very personal essence in purpose, and their subjectivity is up for discussion.

Do we go for 15- or 30-round mags?

Do we go for red dots or iron sights?

The choice is yours.

How to Minimize Costs while Building an AR-15

When browsing your complete AR-15 kits under $300, always go for the stuff that’s necessary and the stuff you don’t have.

This means avoiding all the popular “must-have” accessories. Stuff like muzzle brakes, tactical gadgets, lights, night vision optics, or even fancy grips are all cool but ultimately non-essential for budget shooters.


We hope that you’ve gained the proper insight before you start browsing the cheapest AR-15 kits for under $300. It’s always fun to tweak your own platform and make it as personal as possible.

Just remember to keep your budget in mind, consult with other firearm experts, and make sure you try the aftermarket parts before you purchase them. Expensive doesn’t mean better.

Feel free to take a look at our wide variety of aftermarket parts at Mid State Firearms.

Stay safe, shoot straight.

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