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Let’s assemble an AR-15 lower! An AR-15 lower receiver assembly might sound intimidating, but it’s easier than it looks. This guide breaks down every step to build your AR-15 lower from scratch—no guesswork, no stripped threads, and no flying springs. Whether it’s your first build or your tenth, this walkthrough helps you get it done right the first time. Let’s assemble an AR-15 lower
The bolt catch always gave me the most grief when I was learning. If you scratch the finish here, it’s because you didn’t stabilize it right.
— Jason Schaller
Frequently Asked Questions About Assembling an AR-15 Lower
What tools do I need to assemble an AR-15 lower?
You’ll need a small hammer, roll pin punches, needle-nose pliers, an armorer’s wrench (optional), and a bench block. A vice and lower receiver vise block help but aren’t required.
Can I assemble an AR-15 lower without special tools?
Yes, but it’s harder. You can use improvised tools like a flathead screwdriver and punch alternatives, but a proper roll pin punch set and bench block make the job safer and cleaner.
What’s the hardest part to install on an AR-15 lower?
The bolt catch roll pin is often the trickiest due to its tight space and risk of scratching the lower. A starter punch or tool like the Real Avidpunch set makes it easier.
Do I need to install the buffer tube before the stock?
Yes. The buffer tube must be installed first, as the stock locks into it. The detent and spring under the tube must also be seated correctly during install.
What’s different between building an AR-15 and an AR-10 lower?
Most steps are the same, but the AR-10 uses a threaded bolt catch instead of a roll pin, and some internal dimensions may vary depending on the manufacturer.
Wrap-Up
Assembling an AR-15 lower might seem daunting, but it’s one of the most satisfying parts of building a rifle. Each pin, spring, and detent has its place—and once it’s all together, you’ll know your firearm inside and out. Whether you’re doing a custom build or replacing parts, this guide takes the guesswork out and gets you across the finish line with confidence.
Covers field stripping, upper teardown, lower teardown, lower assembly, and full upper builds—everything needed to break down and rebuild your rifle the right way.
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Credits:
Original Content by The Rogue Banshee / My Rogue Solutions LLC. Credit: Jason Schaller Email: jschaller@trb.fyi
About the Author: Jason Schaller is a former FFL holder and founder of Eagle Eye Shooters Supply in Helena, MT, where he provided professional gunsmithing services and guided customers on all aspects of firearms ownership. Today, he teaches DIY gunsmithing at The Rogue Banshee and serves as a Chief Instructor at Freedom Crew University. With over a decade of hands-on professional experience with firearms and nearly 30 years in IT, Jason also holds top cybersecurity certifications including CISSP, CISA, and CRISC. When he’s not geeking out, he’s helping others build self-reliance, critical thinking, and firearms proficiency through real-world content.
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The videos, articles, and images shared by The Rogue Banshee feature gear, tools, and products for informational and entertainment purposes only. All activities follow local, state, and federal laws where they were conducted in. All activities are conducted safely under professional supervision in approved locations.
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I promote safe and responsible firearm ownership. All activities are conducted in a controlled, professional environment.
