CM10 338 Federal 18″ AR10 Rifle FDE Metallic and Coyote

338 Federal Rifle 18″ AR10 | Unstoppable Big-Game Power

This is a 338 Federal rifle from Chattahoochee Munitions. We have been building in less-mainstream calibers since our inception, on both AR and bolt-action platforms. 8.6BLK, 243 Win, 22-250 Rem, 338 Spectre, 400 Legend, 338 Federal, etc. Experience building with various lowers, uppers, and handguards, both low- and high-profile, allowed us to weigh the pros and cons and create our perfect version of the rifle.

This will be one of the sturdiest-feeling weapons, as everything is designed in tight tolerances. All of our rifles are equipped with HIPERFIRE (High Performance Firearms) Triggers; all are 2.5lb single stage Reflex (curved) or Competition (straight with shoe) or X2S Mod3 2-Stage; Reflex is pictured, Odin Adjustable Buffers, and Superlative Arms adjustable gas blocks.

CM10 Upper and Lower Receiver:

• SR25 Pattern though DPMS High Profile specs such as 16TPI barrel nut, barrel extension, and BCG compatibility

• CNC machined from 7075-T6 billet aluminum

• Lightweight FCG Faces and Mag-well

• Lightweight Cuts on Upper with no Forward Assist

• Pictogram style Fire/Safe engravings on both sides

• Integral trigger guard for added overall strength

• Machined (not broached) Mag-well with wide flare

• Black Tungsten Cerakote

Lower Parts:

• CM Ambi Safety

• CM Ambi Mag Release

• CM10 Pivot and Takedown Pins

• HIPERFIRE 2.5lb single stage Reflex (curved) or Competition (straight with shoe) Trigger and pins, or Hiperfire X2S Mod3 2-Stage – pictured with Reflex

• CM10 Ambi Bolt Release

• B5 Systems Black Grip

Receiver Extension:

• B5 Systems Bravo Stock – Black

• CM Milspec Buffer Tube – Black Tungsten Cerakote

• QD Endplate

• Odin Adjustable Buffer AR10

Upper:

• CM10 Low Mass Bolt Carrier Group

  • 9310 steel HPT Bolt (High Pressure Tested/ Proof)

  • MPI Bolt (Magnetic Particle Inspected)

  • Shot Peened Bolt

  • Nitride-coated bolt

  • Nitride-coated Carrier

  • Nitride-coated Gas Key

  • Gas Key Hardened to USGI Specifications

  • Grade 8 Hardened Fasteners

  • Key Staked Per Mil-Spec

  • Tool Steel Extractor

  • T.E.A Extractor Spring

  • Black Extractor Insert

  • Mil-Spec Crane O-Ring

• CM10 Ambi Charging Handle – 7075 Aluminum

• CM Rifle Length Gas Tube – Melonite

• Superlative Arms .750 Adjustable Gas Block – Melonite

• CM10 LWS 15″ MLOK Handguard – Black Tungsten Cerakote

  • 6061 Aluminum

  • Dual Taper Attachment System

  • Steel Barrel Nut

  • QD Attachment at 3 and 9 o’clock positions

  • MLOK attachment on sides and bottom

  • Full Picatinny Top Rail

• B5 Systems Black Rail Covers

• Pictured with Silencerco ASR muzzle device; can sub for Rugged, Dead Air Keymo, Yankee Hill, Q Cherry Bomb

Barrel: 338 Federal Rifle

• CM 338 Federal 18″ Barrel

• 416R Stainless Steel

• 1:10 Twist

• 5/8×24 thread pitch

• .750 gas journal

• 5R Rifling

• Tactical Grey Cerakote

Magazine:

• 1x10rd PMAG 7.62 Black

OAL: 35″ to 38.250″

OAW: 7lb/14oz with unloaded magazine and no accessories (Weight and dimensions on other tab are for shipping purposes)

LOP: 11.875″ – 15.25″

Warranty – Limited Lifetime

• Limited to original purchaser

• Limited regarding functional performance

• Limited regarding original configuration

Dominate Big Game with the Custom CM10 338 Federal Rifle

When standard hunting calibers fail to deliver the immediate stopping force required in dense brush or rugged mountain terrain, a custom-built 338 Federal rifle stands out as the ultimate solution. Engineered on Chattahoochee Munitions’ signature CM10 chassis, this 18″ semi-automatic firearm brings big-bore knocking power directly into a fast-cycling AR10 platform. Forget heavy, long-action magnum rifles—this setup delivers supreme downrange terminal performance with lightning-fast follow-up speed.

Whether you’re hunting elk, moose, black bear, or large wild hogs, our custom semi-auto 338 Federal rifle offers the perfect balance of hard-hitting energy, maneuverability, and smooth cycling reliability.

Precision Engineering & Match-Grade Component Selection

Every single 338 Federal rifle hand-assembled in our Roswell, Georgia custom shop is built to ultra-tight machining tolerances. We eliminate upper-to-lower wobble and hand-tune gas delivery so your firearm runs flawlessly in any condition:

• 18″ 416R Stainless Steel Barrel: Cut with 5R rifling and a 1:10 twist rate, this barrel stabilizes heavy 180gr to 225gr+ .338 projectiles with surgical downrange accuracy. A Tactical Grey Cerakote coating shields the steel against moisture and field wear.

• Superlative Arms Adjustable Gas Block: Managing heavy gas volume is critical for big-bore AR platforms. Featuring patented forward bleed-off technology, this gas block vents excess pressure forward, softening felt recoil, reducing dirty blowback, and optimizing suppressed operation.

• HIPERFIRE Match Trigger System: Experience a crisp 2.5lb trigger pull equipped standard. Choose between the curved Reflex single-stage, Competition straight-shoe single-stage, or the X2S Mod3 2-stage trigger for match-grade shot control.

• Odin Adjustable Buffer & Low-Mass BCG: Coupled with our HPT/MPI tested low-mass bolt carrier group, the Odin adjustable buffer absorbs heavy rearward impulse, keeping your crosshairs on target for fast follow-ups.

Technical Specification Breakdown

Component / Spec	Details & Manufacturing Standards
Primary Caliber	.338 Federal
Platform Model	CM10 Semi-Auto (338 Federal rifle)
Barrel Spec	18″ 416R Stainless Steel with 5R Rifling, 1:10 Twist
Muzzle Pitch	5/8×24 Thread Pitch (Selectable Brakes & Muzzle Hogs)
Receiver Billet	CNC Machined 7075-T6 Billet Aluminum (DPMS High Profile Spec)
Cerakote Coating	Premium Black Tungsten Finish (Upper, Lower & Handguard)
Trigger System	2.5lb HIPERFIRE (Reflex, Competition, or X2S Mod3 2-Stage)
Handguard	15″ CM10 LWS M-LOK Handguard with Full Top Picatinny Rail
Gas System	Rifle-Length with Superlative Arms Adjustable Gas Block
Unloaded Weight	7 lbs 14 oz (Without optic or accessories)

The Ballistic Edge of a Semi-Auto .338 Federal Rifle

Derived by necking up a standard .308 Winchester case to fire .338 caliber bullets, the 338 Federal rifle produces approximately 15% more energy downrange than a standard .308 Win at short and medium distances. It pushes heavy, high-energy bullets at impressive velocities, delivering high hydrostatic shock and deep penetration on big game.

By chambering this cartridge in our gas-operated semi-automatic CM10 system, your 338 Federal rifle absorbs significant recoil, giving you the energy of a big-bore cartridge with the manageable control of an AR platform.

Factory Customization & Suppressor Readiness

Select your exact build options directly at checkout to customize your 338 Federal rifle for your specific hunting setup:

1. Suppressor Host Muzzle Devices: Outfitted standard with top quick-detach muzzle options including the SilencerCo ASR Brake, Dead Air Keymo Brake/Flash Hider, Q Cherry Bomb, Rugged Brake/Flash Hider, or Yankee Hill Brake.

2. Match-Grade Trigger Shoes: Choose the classic curved Reflex trigger for gloved hunting hands, the straight Competition shoe for bench precision, or the X2S Mod3 two-stage for extra pull control.

3. B5 Ergonomics Package: Fitted with a B5 Systems Bravo Stock, B5 Pistol Grip, and M-LOK Rail Covers for an aggressive, tactile hold under wet field conditions.

Helpful Links & Related Products

• Explore the CM10 Family: Browse our full lineup of big-bore platforms in the CM10 AR10 Collection, including our CM10 308 Win Rifle and CM10 7mm-08 Rem Rifle.

• Small-Frame AR Builds: Looking for light, compact firearms? Check out our full line of CM15 Firearms.

• Ammunition & Suppressor Specs: Review factory ammunition data on Federal Premium Ammunition or explore compatible silencers via the Silencer Shop Network.

Frequently Asked Questions (FAQ)

1. What makes a semi-auto 338 Federal rifle better than a bolt-action rifle?

A semi-automatic 338 Federal rifle provides the stopping power of a .338 caliber bullet while giving you lightning-fast follow-up shot capability. Our adjustable gas block and custom buffer system drastically reduce felt recoil compared to a traditional bolt-action rifle.

2. Which magazines fit this 338 Federal rifle?

Because the .338 Federal shares its parent case dimensions with the .308 Winchester, this 338 Federal rifle feeds reliably out of standard AR10 / SR25 pattern 7.62x51mm magazines, such as the included 10-round Magpul PMAG.

3. Can I run a silencer on this 338 Federal rifle?

Yes! The 18″ 416R stainless barrel is threaded in standard 5/8×24 pitch and features a Superlative Arms adjustable gas block. You can select your preferred muzzle adapter (SilencerCo, Dead Air, Q, YHM, Rugged) at checkout to easily tune gas flow for suppressed shooting.

4. What upper and lower receiver pattern is used?

Our CM10 receiver set is CNC machined from 7075-T6 billet aluminum following SR25 pattern dimensions and DPMS High Profile specifications (including 16TPI barrel nut threads) for maximum component compatibility.

5. What is the current lead time for custom rifle orders?

Current custom build lead time for the CM10 338 Federal rifle is approximately 2 weeks from purchase date to shipment to your local FFL dealer.