AR-10 – .300 RSAUM

Description

AR-10 .300 RSAUM Custom Barrel

We make this AR-10 barrel in .300 RSAUM. Take a look through the available barrel options and the information below before ordering.

Why .300 RSAUM?

.300 RSAUM is short for .300 Remington Short Action Ultra Magnum. It’s a distinct .30-caliber magnum cartridge, not simply another label for .300 WSM or .308 Winchester.

Its cartridge case and chamber are specific to RSAUM. Ammunition and compatible AR-pattern components can be more specialized than the common .308 platform.

Customize Your AR-10 Barrel

• Material and twist: Choose the available barrel steel and rifling twist specifications for this product.
• Length and muzzle: Review the available lengths and muzzle finishes.
• Gas system and barrel profile: Check the gas-system, gas-tube and gas-block size options, including which combinations are offered together.
• Finishing: Fluting, Cerakote and other finishing choices may depend on the barrel configuration.
• Other components: Pay attention to any bolt, bolt-head or customer-supplied component choices.

Before You Order

• Check your platform: AR-10-pattern rifles aren’t all identical. Confirm your receiver, bolt and other relevant components.
• Check your ammunition: Use ammunition specifically appropriate for .300 RSAUM.
• Confirm your order: This is a custom-made barrel, so review every selected specification and any separately supplied components.

Fitment note: Confirm specialized magnum-related components and platform fitment before ordering.

Barrel Options Explained

CM and SS: CM is chrome-moly steel, which needs protection against rust. SS is stainless steel, which resists corrosion better but still needs regular care. Check the listed material/twist choices for this chambering.

Twist rate: A marking such as 1:10 means the rifling makes one complete turn over ten inches. It isn’t a barrel-length measurement.

Gas-system length: The selections for this barrel include Rifle-length (about 12 inches) and magnum-length (about 14 inches). These describe nominal gas-system layouts, not barrel length or the tube’s exact measured length.

What is a gas tube? In a conventional AR system, the gas block directs some gas through a small tube toward the action. The tube is a separate component from the barrel and gas block. If you need one supplied, review the Add Gas Tube? option where offered. Gas-tube selection corresponds to the applicable gas-system layout.

Barrel profile: This barrel offers SOCOM and HBAR contours. These describe the barrel’s exterior shape and amount of material. A lighter contour generally weighs less, while heavier contours have more material.

Gas-block size and selection: This product shows .750 and .875-inch gas-block mounting sizes. Those numbers describe the barrel’s outside diameter at the mounting area, not bullet caliber. The block can be selected as an add-on where offered. This product lists adjustable gas-block add-ons. Customers with their own compatible block can choose a no-block option where available; matching diameter alone doesn’t establish full compatibility.

Muzzle finishes: A target crown is an unthreaded muzzle finish. The threaded option for this barrel is 5/8×24. Magna Port uses gas-venting cuts near the muzzle intended to help manage muzzle rise; it isn’t a screw-on attachment. Gill Cut is a specialty gill-style muzzle cut. Ask us about the current pattern rather than assuming it works like porting or threads.

Q / SIG taper (optional, no extra taper charge): Standard 5/8×24 muzzle threads typically have a flat, 90-degree shoulder behind them. The Q / SIG option uses those same threads with a 25-degree angled shoulder instead. Certain Q- and SIG-style muzzle devices and suppressor mounts are made to seat against this taper, giving the mount its intended contact surface. Why choose it? It is a fitment choice: select 5/8×24 Threads + Q/SIG Taper if your specific mount calls for a 25-degree taper, or choose standard 5/8×24 threads if it calls for a flat shoulder. The taper does not change the thread size or automatically improve accuracy. There is no extra taper charge beyond any existing threading cost. Check your mount specifications or ask Deadshot if you are unsure.

Fluting restrictions: Some fluting and muzzle-finish combinations aren’t offered together. The product choices reflect those limitations.

Barrel extension: This steel component at the rear of the barrel provides the locking surfaces for the bolt. It isn’t the gas block.

Fluting and finishes: Fluting cuts grooves along the outside of the barrel. Cerakote and other listed finishes affect appearance and surface protection.

What Happens After You Order?

We make the barrel to the specifications on your order. The current estimated production time is 3–8 weeks, not a guaranteed delivery date. Contact us promptly about corrections or updates.

Common Questions About This Barrel

Questions Before You Order?

Still comparing options? Our Barrel FAQs explain barrel materials, twist rates, common terminology, ordering and care.

Questions about .300 RSAUM or your AR-10 rifle? Email us about this barrel or use our Contact page.

Returns and warranty

All sales are final by default. Discretionary return requests are reviewed individually and require prior approval. If a discretionary return is approved, a 25% restocking fee applies. A 15% cancellation fee applies after work has started. We evaluate manufacturing-defect concerns under our warranty and address covered issues through an appropriate remedy. Read our Refund Policy and Terms of Service.