Model 307™ MZY
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Model 307™ MZY

Price range: $2,699.00 through $2,849.00

The Model 307 MZY is Weatherby’s first ever muzzleloader built for hunters who want centerfire performance in a front end loader. Designed around the modular Model 307 platform the MZY brings a new standard of precision to the world of modern muzzleloading. At the heart of the MZY is the Arrowhead Gen2 Ignition System. Typically only found in the custom gun world, this sealed rifle primer design solves the problem of other ignition systems. By using precision fit primer modules with large rifle primers, the system delivers hotter and more consistent ignition through a short straight flame path while fully sealing the breech. This eliminates blowback, protects the action, and maintains repeatable headspace shot after shot. Available in both 45 and 50 cal options, the MZY has options that are compliant in many western states.

FINISH

Receiver / Barrel / Bolt / Bolt Knob / Accubrake DST – Graphite Black Cerakote
Stock – Exposed carbon fiber with black sponge pattern accents

TECH SPECS

View Tech Specs

SKU: 3MZY Categories: , Tag:
Made in the USAProudly Made in USA

Description

Model 307 MZY Designed for modern muzzleloading.

A quick overview of the MZY system and what sets it apart in the field.

IGNITION SYSTEM

Arrowhead Gen2 Ignition System

The game changer behind the Model 307 MZY.

Traditionally found in custom muzzleloaders, Arrowhead’s Gen2 Ignition System brings sealed, consistent ignition to a production muzzleloader, built around the Model 307 platform.

Full breakdown on Arrowhead Gen2 Ignition System

The Arrowhead Gen2 Ignition System features a sealed rifle primer design that eliminates the common problems found in other muzzleloader systems.

Precision fit primer modules (.473) paired with large rifle primers create hotter and more consistent ignition through a short straight flame path while fully sealing the breech. This prevents blowback, maintains repeatable headspace, and delivers reliable performance across a wide range of conditions.

The result is cleaner operation, tighter velocity spreads, and excellent cold weather dependability when using Blackhorn 209. Each MZY comes with 20 unprimed modules for you to use.

Included: 20 unprimed, reusable primer modules.

Additional: Extra unprimed modules sold separately.
Shop unprimed modules

RECOMMENDED LOAD

Confidence, measured.

Weatherby’s recommended load is built around consistency you can trust.

Weatherby recommends 105 grains of Blackhorn 209 by weight (or 150 grains by volume) paired with Hornady® Bore Driver® bullets for consistent, multi-state compliant performance in the MZY. The 280 Grain .45 Cal and the 340 Grain .50 Cal Bore Drivers have proven to deliver dependable accuracy across a wide range of hunting conditions.

Powder
Blackhorn 209 — 105 grains by weight or 150 grains by volume
Bullets
Hornady Bore Driver (caliber-specific)
• 280gr - .45 Cal
• 340gr - .50 Cal
Shop Bore Driver bullets
Always follow published load data and safety guidance. Verify components for your specific configuration.
Field tip: Measuring by weight (not volume) helps keep ignition and velocity more consistent from shot to shot. We recommend Blackhorn 209 to be measured by weight rather than by volume because weight provides much better consistency and precision.

Included: Cedar Mountain Quick Loaders for fast, consistent field reloads—even when running a MZYbrake.

Available & recommended accessories

Hornady Bore Driver bullets for consistent, caliber-specific performance. Shop bullets

Cedar Mountain Quick Loaders speed up field reloads—no separate funnel required. Shop quick loaders

Included

What’s included with every MZY.

Standard equipment included with every Model 307 MZY. (Optional sights vary by model and are called out separately.)

  • Unprimed primer modules

    Reusable modules included with every rifle.

    Qty 20 unprimed modules

  • Breech plug

    Sealed system component built for consistent ignition.

  • Breech plug wrench & socket

    Tools to keep your setup serviceable.

    Includes socket, wrench and extender

  • Cedar Mountain Quick Loaders

    Streamlined loading without extra funnels.

    Kit includes 3 powder tubes, 1 quick loader

  • Collapsible ramrod + carry case

    Designed to stay separate—where it belongs.

    Notes Jag included with ramrod

Accessories

Build the system.

Additional accessories and consumables designed to expand your setup based on conditions and preference. Shop All MZY Accessories

Quick Loader Kit

Additional Cedar Mountain Quick Loaders to streamline reloads when cold, wind, or low light makes loose powder difficult.

Sold separately • Ships separately from the muzzleloader

Shop quick loaders

Unprimed MZY Modules (20 pack)

Additional unprimed modules for a faster field setup. Unprimed modules are included with every MZY additional unprimed modules available separately.

Sold separately • Ships separately from the muzzleloader

Shop unprimed modules

Hornady Bore Driver Bullets

Caliber-specific Bore Drivers matched to Weatherby’s recommended load for consistent, repeatable performance.

Sold separately • Ships separately from the muzzleloader

Shop Bore Drivers

Additional accessories will ship separately and may arrive before or after the muzzleloader. Firearms ship to a licensed FFL dealer.

Sights

Sight configurations & upgrades.

Choose a factory configuration, then upgrade separately if desired.

Optional Factory configuration

  • Sight Option: Williams Precision: Standard Sight Set
  • Select Modals: Factory-installed on select models.

Factory-installed • Ships with the muzzleloader

Additional upgrade option (Sold Separately)

Williams Precision Micro Adjustment Sight Set is sold separately and intended for aftermarket installation. It does not replace factory-installed sights and will not ship installed on the muzzleloader.

Sold separately • Not factory installed • Ships separately from the muzzleloader

Shop upgrade

How-To

Get the most from your MZY.

Short, practical walkthroughs covering setup, loading, maintenance, and field tips.

Shipping note: Model 307 MZY ships to a licensed FFL dealer. Accessories ship separately to your address and may arrive at different times.

The why behind the MZY

Tags over points.

Across the West and beyond, opportunity is harder to come by. Premium rifle tags take years, sometimes decades to draw. For many hunters, waiting has become part of the game. But not everyone is willing to wait.

At Weatherby, hunting is more than a pastime. It is a pursuit driven by purpose. Every product we build is designed to create opportunity and extend what is possible in the field. “Tags over points” is not just a slogan. It’s a mindset. It’s for hunters who choose opportunity over waiting. Engineered for hunters unwilling to compromise, the MZY stands as the ultimate tool for those who demand more from every hunt.

See state muzzleloader regulations
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LEARN MORE

Episode 149 - The Model 307 MZY: Weatherby's First Ever Muzzleloader
On Our Mark Podcast

Episode 149 - The Model 307 MZY: Weatherby's First Ever Muzzleloader

We’re proud to announce the introduction of the Model 307 MZY to the Model 307 lineup. This historic addition is Weatherby’s first ever muzzleloader and is loaded with features. Combining a Peak44 Bastion stock with the Arrowhead Precision Gen2 Ignition system, this precision muzzleloader was made for superior accuracy for when it matters most.

LISTEN NOW

FEATURES

TriggerTech Trigger

TriggerTech’s trigger provides true zero-creep break, extremely short over-travel, and is externally adjustable (down to 2.5 lbs). Precision cut stainless steel components ensure consistent trigger pulls from shot to shot in a safe, reliable, and corrosion resistant package. Features a 2 position safety.

Tool-less Bolt Takedown

The Model 307 showcases an all-new 3 piece bolt design, featuring a completely tool-less takedown.

MZYbrake

The MZYbrake is a side-ported directional self-timing brake. Side-ported brakes direct gases to the left and right reducing muzzle rise and drastically reducing felt recoil. A timing nut allows users to easily self-time the brake without the aid of a gunsmith.

Carbon Fiber Stock

Sourced from Peak 44, this stock has the distinction of being the lightest production aerospace-grade carbon fiber stock on the market. Industry-leading manufacturing techniques, patented bedding technology and the addition of the 3DHEX recoil-reducing buttpad mean this is one of the most advanced lightweight stocks to date.

Cerakote®

Cerakote is the industry leading thin-film ceramic coating. The Cerakote unique formula enhances physical properties including wear, corrosion, and chemical resistance while improving impact strengths, and hardness.

FEATURES

TriggerTech Trigger

TriggerTech’s trigger provides true zero-creep break, extremely short over-travel, and is externally adjustable (down to 2.5 lbs). Precision cut stainless steel components ensure consistent trigger pulls from shot to shot in a safe, reliable, and corrosion resistant package.

Tool-less Bolt Takedown

The Model 307 showcases an all-new 3 piece bolt design, featuring a completely tool-less takedown.

MZYbrake

The MZYbrake is a side-ported directional self-timing brake. Side-ported brakes direct gases to the left and right reducing muzzle rise and drastically reducing felt recoil. A timing nut allows users to easily self-time the brake without the aid of a gunsmith.

Carbon Fiber Stock

Sourced from Peak 44, this stock has the distinction of being the lightest production aerospace-grade carbon fiber stock on the market. Industry-leading manufacturing techniques, patented bedding technology and the addition of the 3DHEX recoil-reducing buttpad mean this is one of the most advanced lightweight stocks to date.

Cerakote®

Cerakote is the industry leading thin-film ceramic coating. The Cerakote unique formula enhances physical properties including wear, corrosion, and chemical resistance while improving impact strengths, and hardness.

TECH SPECS

Caliber
Weight
Overall Length
Mag capacity
Barrel Contour
Barrel Threads
Barrel OAL
Twist Rate
Length of Pull
Drop @ Comb
Monte Carlo
Drop @ Heel
.45 CAL7.1lbs.45“N/A#43/4-2428" (26" barrel + 2" brake)1:20“13.25“.49“N/A.35“
.50 CAL7.1lbs.45“N/A#43/4-2428" (26" barrel + 2" brake)1:24“13.25“.49“N/A.35“
Caliber
Weight
Overall Length
Mag capacity
Barrel Contour
Barrel Threads
Barrel OAL
Twist Rate
Length of Pull
Drop @ Comb
Monte Carlo
Drop @ Heel
.45 CAL
7.1lbs.
45“
N/A
#4
3/4-24
28" (26" barrel + 2" brake)“
1:20“
13.25“
.49“
N/A
.35“
.50 CAL
7.1lbs.
45“
N/A
#4
3/4-24
28" (26" barrel + 2" brake)“
1:24“
13.25“
.49“
N/A
.35“

Additional information

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