No blowback. All confidence.
Sealed primer module ignition designed to keep the action clean and consistency high.
Weatherby Model 307 MZY
Front Loaded. Forward Thinking.
Weatherby's first muzzleloader, built on the Model 307 platform with sealed ignition and configuration options designed for muzzleloader seasons.
Caliber
Sights
Built for traditional muzzleloader seasons.
Arrowhead Gen2 Ignition System.
Custom tech. Production ready.
This is the game changer. A sealed primer module ignition system designed to keep the action cleaner, ignition more consistent, and confidence high especially in the cold.
Traditionally, this level of ignition performance lives in custom builds. The MZY brings it to a production muzzleloader, built on the Model 307 platform.
Arrowhead Gen2 Ignition System
Sealed Primer Module Ignition
A sealed primer module ignition system that keeps blowback contained and helps the action stay cleaner over long strings and harsh conditions.
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Season Ready Options
Choose your season setup.
| Configuration | Caliber | Sights | |
|---|---|---|---|
| .45 / No Sights | .45 | No Sights | |
| .45 / Sight Set | .45 | Williams Precision Standard Set | |
| .50 / No Sights | .50 | No Sights | |
| .50 / Sight Set | .50 | Williams Precision Standard Set |
Sight Options
Open sights
Traditional and fast—ideal for many season requirements and quick shots in tight cover.
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. Field Tip: Measuring powder by weight—not volume—ensures greater precision and repeatability shot to shot.
Powder: Blackhorn 209 - 105 grains by weight or 150 grains by volume
Bullets: Hornady Bore Driver (caliber-specific)
• 280gr. - .45 Cal
• 340gr. - .50 Cal
Always follow published load data and safety guidance. Verify components for your specific configuration. Do not overfill your included Cedar Mountain Quick Loaders, they will only hold 150 grains of powder by weight.Cedar Mountain Quick Loaders
When cold, wind, low light, or adrenaline make loose powder loading difficult, Cedar Mountain Quick Loaders streamline the process, no separate funnel required, even when running an MZYbrake. Compatible with both .45 and .50 caliber MZY configurations.
Shop Quick Loaders
Included accessory
Packed Smart. Where it Belongs.
Collapsible ramrod & dedicated carry case, built for organized field use.
The MZY includes a collapsible ramrod and custom carry case for clean, secure storage in the field. Keeping the ramrod separate helps preserve the precision expected from the Model 307 platform.
Why not barrel-mounted?
Ramrods that ride against the barrel can transfer vibration. A separate, collapsible design keeps the barrel clean and consistent shot to shot.
- Collapsible for compact storage
- Dedicated carry case keeps gear organized
- No barrel contact to help maintain consistency
Accessories
Build the System.
Accessories designed to keep your setup simple, consistent, and ready for the season.
