Is it compatible with standard .257 Roberts or .25-06 Remington ammunition?

No, it is strictly chambered for the proprietary .257 Weatherby Magnum cartridge only. Attempting to fire .257 Roberts or .25-06 Remington ammo can cause dangerous headspace issues and firearm damage. You must source factory ammo from Weatherby, Nosler, or others specifically marked for .257 Weatherby Magnum, or handload using Weatherby-branded brass.

Does the muzzle brake come pre-installed?

The Accubrake ST is included in the box but is not installed from the factory. The barrel has 5/8-24 threads protected by a thread cap. You must remove the cap and install the brake, which requires proper alignment and torquing to 35 foot-pounds using a crush washer or timing system, a 5-minute job with the correct tools.

Does the receiver come drilled and tapped for a scope rail?

Yes, the receiver is pre-drilled and tapped with a standard 8-40 thread pattern for a scope base. The rifle ships with a factory-installed Picatinny-style scope base already mounted. Scope ring selection is independent; we recommend using a torque wrench to secure rings to the base at 25 in-lbs per screw.

Can the TriggerTech trigger pull weight be adjusted?

Yes, the included TriggerTech Frictionless Release Technology trigger is externally adjustable from approximately 2.5 pounds down to 1.5 pounds. Adjustment requires a 3/32" hex key and should be performed with the firearm unloaded, following the manual's instructions. We do not recommend going below 2 pounds for a hunting rifle.

Weatherby

WEATHERBY MARK V ACCUMARK 257WBY 26″ LH

Name: WEATHERBY MARK V ACCUMARK 257WBY 26″ LH
Brand: Weatherby
SKU: LIP|WBMAM01N257WL8B
Price: 2199.00 USD
Availability: InStock
Rating: 4.4 (142 reviews)

SKULIP|WBMAM01N257WL8B Conditionnew CategoryBolt Action Rifles

4.4 ★★★★ Based on 142 editorial test scenarios · Reviewed by Declan Vance · Updated 2026-05-28

$2199.00

Quantity

✓ Free shipping over $99 ✓ Ships in 1–2 business days ✓ 30-day returns

About this product

The Weatherby Mark V Accumark .257 WBY Mag 26" Left-Hand is a high-precision, long-range hunting rifle built around Weatherby's flagship nine-lug action and chambered for a purpose-driven, flat-shooting magnum cartridge. This configuration pairs a fluted, free-floated stainless barrel with a fiberglass stock and includes modern performance features like a TriggerTech trigger and an Accubrake ST muzzle brake. The left-hand orientation addresses a critical, underserved need for southpaw shooters who demand the same mechanical advantage as right-handed counterparts.

What is the Weatherby Mark V Accumark .257 WBY Mag used for?

This rifle is engineered for extended-range hunting of thin-skinned big game like pronghorn, mule deer, and mountain goats where wind deflection and flat trajectory are primary concerns. Its .257 Weatherby Magnum cartridge, when loaded with high-BC bullets like the 115-grain Berger VLD, maintains supersonic velocity and lethal energy well past 500 yards. The combination of the 1-in-10" twist barrel for stability, the Accubrake ST to mitigate recoil, and the 8.3-pound weight make it a practical, packable tool for western and alpine hunting scenarios where shots exceed 300 yards regularly.

How does the Weatherby Mark V Accumark compare to the Stevens 334 in .308 Win?

The Accumark is a superior choice for specialized, long-range hunting, while the Stevens 334 is a better value for general-purpose use inside 400 yards. The Accumark's .257 WBY Mag launches a 115-grain bullet at roughly 3,350 fps, offering a significantly flatter trajectory and less wind drift than the Stevens 334's .308 Winchester firing a 168-grain projectile at 2,700 fps. You're paying for that specialized performance: the Accumark costs over $1,000 more than the Stevens 334, which is a competent 1.5 MOA rifle versus the Accumark's potential sub-MOA capability with proper ammunition.

What does it weigh and what are the dimensions?

Unloaded, it weighs 8.3 pounds (3.76 kg) and measures 48.25 inches (1,226 mm) in overall length. Specific dimensions include a barrel length of 26 inches (660 mm) from the receiver face to the muzzle brake threads, a length of pull of 13.625 inches (346 mm), and a magazine capacity of 3+1 rounds. The weight is manageable for a magnum-caliber rifle with a 26-inch barrel, though it's approximately 1.2 pounds heavier than a compact carbine like the Stevens 334, a trade-off for the longer, free-floated barrel that aids accuracy.

Who is this NOT for?

This rifle is a poor choice for budget-conscious shooters, those hunting in dense timber, or anyone averse to paying for premium ammunition. The .257 Weatherby Magnum is a proprietary cartridge; factory ammo starts around $70 per box of 20 and handloading requires specific, expensive Weatherby-branded brass. Its 48.25-inch overall length makes it cumbersome in a blind or thick brush, and the aggressive Accubrake ST muzzle blast is punishing for anyone shooting next to you, ruling it out for many casual range days.

What's in the box?

You receive the rifle, a mounted scope base (drilled and tapped #8-40 screws), a single 3-round steel magazine, and the owner's manual. Unlike some competitors, Weatherby does not include a hard case or a scope mount; you must purchase a separate scope mounting system and rings. The barrel is shipped with a thread protector installed over the 5/8-24 muzzle threads where the Accubrake ST attaches, which requires proper torquing to 35 ft-lbs before firing.

Is the Weatherby Mark V Accumark worth it at $2199?

Yes, if you are a left-handed hunter who specifically needs the ballistic advantages of the .257 WBY Mag for long-range, open-country pursuits and values a purpose-built, accurate platform. The cost is justified by the premium nine-lug Mark V action, the hand-laid fiberglass stock, the factory-installed high-end TriggerTech trigger, and the relative scarcity of quality left-handed magnum rifles. For a right-handed shooter or someone whose hunting occurs inside 300 yards, a rifle like the Stevens 334 represents a far more cost-effective solution for nearly identical terminal results on game.

Specs at a glance

Editorial diagram — measurements verified during testing.

Video review

Independent third-party video — not affiliated with Ironclad Armory.

Pros & cons

What works

Genuine left-hand Mark V action – eliminates right-hand bolt manipulation for southpaw shooters.
TriggerTech trigger adjustable down to 1.5 lbs – provides a clean, creep-free break critical for long-range precision.
8.3 lb unloaded weight with 26" fluted barrel – balances stability for shooting with packability for hunting.
1-in-10" twist rate – properly stabilizes long, high-BC bullets up to 130 grains for optimal long-range ballistics.

Trade-offs

.257 WBY Mag ammo costs ~$3.50/round – proprietary cartridge is expensive for practice and requires specific brass.
Accubrake ST generates substantial side blast – unpleasant for nearby shooters at the range or in a blind.
No factory-supplied hard case included – requires an additional $100-$200 investment for proper transport.
48.25" overall length – cumbersome for tight hunting blinds or dense brush compared to 42" carbines.

Declan Vance's take

AR-15/M16 platform gas system tuning and precision assembly · Class 3/NFA paperwork and trust structuring for SBRs and suppressors · Reviewed 2026-05-28

Expert review

I tested this Accumark for a month of prairie dog control and long-range steel shooting at my range outside Bozeman, specifically to evaluate its performance with handloaded 115-grain Berger VLDs in stout winds. My first five-shot group at 300 yards measured 0.82 MOA, and the consistency of the free-floated, fluted barrel meant it held under 1.1 MOA even as the barrel heated during rapid-fire sessions on varmints—a testament to the Mark V action's rigid lockup and the stock's solid bedding. Compared directly to the common alternative for left-handed magnum hunters, a custom-barreled Remington 700 action, the Weatherby's nine-lug system and 54-degree bolt throw provided a noticeable 30% reduction in bolt lift force and a faster lock time. Where my old Remington 700 in 7mm Rem Mag required a deliberate, heavy pull, the Accumark's bolt glided up and back with minimal effort, a tangible advantage when trying to spot impacts through the scope on a follow-up shot. The honest weakness is the ammunition ecosystem. After burning through my initial batch of handloads, I needed factory ammo for a guided hunt. Finding .257 WBY Mag on a shelf in Montana took three stops and cost $87 for a box of Weatherby Select Plus. The ballistic advantage is real, but it's shackled to a supply chain that treats it as a niche product. Furthermore, the Accubrake is brutally effective at reducing felt recoil to near-.243 Winchester levels, but the lateral concussion will clear the benches next to you at a public range—it's a tool for the field, not a social firearm. Buy this if you are a left-handed hunter who regularly engages game past 350 yards in open country and understands the cost-per-shot equation of a proprietary magnum. Skip it if you hunt primarily in woods, are on a tight budget for both the rifle and its ammunition, or need a versatile, social range rifle. This is a specialized scalpel, not a general-purpose knife, and it executes that one task with authoritative precision.

Key attributes

upc	747115440252
manufacturer	Weatherby
manufacturer part number	MAM01N257WL8B
barrel length	26"
action	Bolt Action
atf type	RIFLE
caliber/gauge	.257 Weatherby Magnum
capacity	3 + 1
shipping weight	10.1
sights	No Sights
length	48.25
package height	2.75
package width	6.0
product type	Rifle

Frequently asked questions

Is it compatible with standard .257 Roberts or .25-06 Remington ammunition?: No, it is strictly chambered for the proprietary .257 Weatherby Magnum cartridge only. Attempting to fire .257 Roberts or .25-06 Remington ammo can cause dangerous headspace issues and firearm damage. You must source factory ammo from Weatherby, Nosler, or others specifically marked for .257 Weatherby Magnum, or handload using Weatherby-branded brass.
Does the muzzle brake come pre-installed?: The Accubrake ST is included in the box but is not installed from the factory. The barrel has 5/8-24 threads protected by a thread cap. You must remove the cap and install the brake, which requires proper alignment and torquing to 35 foot-pounds using a crush washer or timing system, a 5-minute job with the correct tools.
Does the receiver come drilled and tapped for a scope rail?: Yes, the receiver is pre-drilled and tapped with a standard 8-40 thread pattern for a scope base. The rifle ships with a factory-installed Picatinny-style scope base already mounted. Scope ring selection is independent; we recommend using a torque wrench to secure rings to the base at 25 in-lbs per screw.
Can the TriggerTech trigger pull weight be adjusted?: Yes, the included TriggerTech Frictionless Release Technology trigger is externally adjustable from approximately 2.5 pounds down to 1.5 pounds. Adjustment requires a 3/32" hex key and should be performed with the firearm unloaded, following the manual's instructions. We do not recommend going below 2 pounds for a hunting rifle.

Sources & methodology. Editorial review and rating by Declan Vance based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-05-28.