Spartan Overthrow AR-15 Build

Overthrow Custom AR-15

Sharps Bro’s “Overthrow” AR-15

Welcome to our blog, where we embark on a thrilling journey to build the Spartan Overthrow AR-15. If you’re an AR-15 enthusiast, a firearms aficionado, or simply curious about assembling a high-quality, custom rifle, you’ve come to the right place. The Spartan Overthrow build is a project that promises to deliver performance and style inspired by the legendary warriors of Sparta. In this blog, we will take you through every step of this build, from selecting components to assembly, and provide insights, recommendations, and insider tips to ensure your AR-15 is not only a formidable tool but also a work of art. So, prepare to channel your inner warrior and join us on this journey as we conquer the world of Spartan Overthrow AR-15 builds.

Spartan Build

The “Overthrow Spartan” build was our second in the Sharps Brothers lower receiver AR15 builds. The first was the “Skull-themed Jack” build. Our team has had a blast making these, and we couldn’t be happier with how they’ve turned out, with a lot of help from our friends at Unique Ar’s, who do amazing custom handguards and Cerakote work.

Below we’ll outline the parts we used and provide video footage of the build and a photo gallery of the final build.

Why Another Themed AR-15?

The SSP Firearms team had such a great time on the first custom-themed AR15 build we have decided to do the whole series of Sharps Brother’s Lower Receivers.

sharps brothers lower receivers jack, overthrow, showdown, warthog, hellbreaker
AR Pistol in Back “The Jack” Left to right Warthog, Overthrow, Showdown, Hellbreaker

We’ll keep detailed information about each build and its parts on our blog and have a separate post tracking all the completed builds. For example, this Overthrow AR-15 build is a .223 Wylde Odin Works Barrel with a Franklin Armory Binary trigger system.

Parts in Our Spartan AR-15 Build

The number of parts in an AR-15 can vary depending on the specific model and configuration, but a typical AR-15 rifle consists of around 100-150 individual pieces. These parts can be broadly classified into 4 categories:

  • Upper Receiver
  • Lower Receiver
  • Furniture and Accessories
  • Small Parts
Custom AR-15 Parts

The small parts make up roughly half the parts. They consist of springs, pins, screws, detents, roll pins, and O-rings. Depending on accessories, the list grows.

Below we’ll outline all the parts and manufacturers that went into this “Overthrow Spartan AR15 build. The details on all the parts are listed below, and please feel free to email or comment with any questions.

Upper Receiver

Sharps Brothers Billet Upper Receiver

Capable of firing .223, 5.56, .224 Valkyrie, 300 BLK, and 6.5 Grendel calibers. Port opening is not large enough for 450 Bushmaster, 458 SOCOM or 50 Beowulf.

Made from 7075-T6, and out of the box, Anodized black, although ours has a Cerakote finish done by the amazing team at Unique AR’s. Comes with a forward assist kit & dust cover installed.

Sharps Brother Upper Receiver Cerakoted for the Battleworn look.

Upper Receiver Specifications:

  • Made from billet 7075-T6 aluminum
  • Mil-Spec Type III hard coat anodize 
  • ‘SHARPS BROS.’ discretely engraved on both sides
  • Weight: 9 oz

Bolt Carrier Group

BCG for an AR-15

Charging Handle

Tactical Galaxy Bronze Ambidextrous Charging Handle

AR-15 bronze charging handle

Charging Handle Specifications

Ejection port cover/dust cover

Tactical Galaxy Ejection Port Dust Cover

Bronze Dust Cover

Dust Cover Specifications

Fits 556, 223, 6.8, 300 AAC
Stamped steel construction.
Cold-Rolled 1045 / 1055 carbon steel
Military specification heavy phosphate coating

Forward Assist

Forward Assist Specifications

Came on the Sharps brother’s upper receiver but was removed for cerakote and then put back in.

Overthrow AR-15 Build Video


Odin Works 18″ .223 Wylde Barrel

.223 Wylde is a hybrid of the .223 REM and 5.56. .223 Wylde has a chamber throat that is tighter than the 5.56 achieving better accuracy but still reliably functional with 5.56 ammunition. All DI barrels include stainless steel tunable gas blocks.

Spartan build barrel

Barrel Specifications

Profile: DMR
Length: 18″
Gas placement: Rifle
Rifling: Button 8 twist
Weight: 2.534 lbs
Made from 416R Stainless Steel
M4 Feed ramps
1/2-28 Threading
1″ MOA guaranteed

Gas System

Odin Works Adjustable Gas Block

Odin Works Gas block and Tube
Gas block and tube with lower receiver parts below

 Stainless steel tunable gas block


Unique AR’s Spartan Handguard

Unique ARS Spartan Handguard
Unique AR’s Custom Spartan Handguard

Handguard Specifications

Free-float handguard made of 6061 T6 Aluminum
Inside diameter 1.75″, exterior diameter 2″
Compatible with any mil-spec AR-15 upper receiver or (DPMS Gen 1 Style) AR-10 upper
Unique-ARs proprietary Picatinny rails

Lower Receiver

Sharps Bro’s Overthrow AR-15 Lower Receiver

Sharps Bros Overthrow is an open magazine well helmet design with battle-worn dents, sword gashes, and crack lines. We went with the Spartan theme, but you could do Viking. The lower comes in Black, but we worked with the talented team at Unique Ar’s, who did the Cerakote finish.

Sharps Brothers Overthrow Receiver

Receiver Specifications

  • Machined top to bottom from 7075-T6 aluminum
  • A hard coat anodize finish per MIL-A-8625
  • Full compatibility with all mil-spec internal parts
  • Full compatibility with all other aftermarket mil-spec upper receivers
  • Full compatibility with GI standard issue magazines as well as PMags
  • Multi caliber mark


Franklin Armory Binary Trigger System

Spartan builds FCG- Binary dropin trigger

Trigger Specifications

  • The release round can be canceled by simply moving our Patented selector out of Binary® mode while holding the trigger back
  • Easy to install * Smooth trigger pull: 4.5 lbs, +/- 0.5 lbs
  • Positive reset on release phase
  • Enhanced buffer springs for optimal flexibility
  • Works in most AR platforms and calibers including 5.56 NATO, 308 Win, 300 BLK, 9mm, Rimfire, etc….
  • Compatible with most Bolt Carrier Groups (BCG)
  • Great for competition shooters, tactical shooters, and recreational enthusiasts

Pistol Grip

Name of pistoil grip

Buffer System and Stock

buffer spring, buffer, buffer tube


Spartan Build Stock

More Overthrow AR-15 Photos

Frequently Asked Custom Build Questions

Is it legal to build my own AR-15?

Yes, it is legal to build your AR-15 for personal use in most states in the US. However, checking your local laws and regulations before starting the build process is important.

What tools do I need to build an AR-15?

Some essential tools you will need for building an AR-15 include:
Armorer’s wrench
Punch set
Vise block
Barrel nut wrench
Torque wrench
Pin starter punch

How much does it cost to build an AR-15?

Building an AR-15 can vary depending on your chosen components, but a basic build can cost around $500-$700. However, the cost can be much more expensive if you choose higher-end components or want to customize your rifle extensively.

How long does it take to build an AR-15?

The build time can vary depending on your experience level and the complexity of the build. For example, a beginner can expect to spend 6-8 hours on their first build, while an experienced builder may be able to complete the build in 2-3 hours and sometimes in half that time.

Do I need to have any prior knowledge or experience to build an AR-15?

No, prior knowledge or experience is not necessary. Still, it is recommended that you do your research and understand how the rifle functions before starting the build process.

Can I customize my AR-15?

Yes, one benefit of building your AR-15 is the ability to customize it to your specific preferences. For example, you can choose different barrel lengths, calibers, trigger assemblies, stocks, handguards, etc…

Do I need any special permits to build an AR-15?

No. Although you do not need special permits to build an AR-15 for personal use, but you should ensure that the rifle complies with all federal and state laws and regulations.


  • Michael Hodgdon

    A firearm, shooting, outdoor, and hunting enthusiast for over 35 years. Thank you all for the suggestions on topics you would like to see; we'll keep posting as you keep sending them in. Please comment; we will try to answer all comments quickly.

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