Mid State Firearms is excited to announce the release of the new OTX Plan B Castle Blast Shield — bringing the compact, proven Castle-style blast shield design to Plan B-compatible muzzle devices.
For shooters who have been looking for a Plan B-compatible Castle blast shield, the wait is over.
A Castle Blast Shield for the Plan B Ecosystem
The original Castle-style blast shield became popular for a simple reason: it offered a compact way to redirect muzzle blast forward without permanently changing the shooter’s muzzle device.
The new OTX Plan B Castle Blast Shield brings that same concept to modern Plan B/Rearden-style muzzle devices.
Instead of the original Castle system’s 13/16×16 mounting interface, the new OTX version uses a .9×24 Plan B/Rearden-style taper-mount interface, allowing it to work with compatible Plan B-style muzzle devices.
That means shooters can now add a Castle-style blast shield to a compatible Plan B muzzle device without replacing the muzzle device itself.
Why Use a Blast Shield?
Muzzle brakes and compensators are excellent at controlling recoil, but the gases they redirect can create substantial side blast and concussion.
That’s not always a problem when shooting alone outdoors. But when you’re shooting around other people, taking a class, shooting from a bench, or using an aggressive muzzle brake on a short barrel, that lateral blast can become much more noticeable.
The OTX Plan B Castle Blast Shield surrounds the muzzle device and redirects muzzle blast primarily forward.
It’s a simple solution for shooters who want the option to change the way their muzzle device behaves depending on the shooting environment.
Run It Two Ways
With a compatible Plan B muzzle device, you can:
Run the muzzle device by itself
for its intended flash-hiding, compensating, or recoil-reducing characteristics.
Add the OTX Plan B Castle Blast Shield
when forward blast redirection is preferred.
The ability to switch between the two configurations gives you more flexibility without having to replace your muzzle device.
Compact and Lightweight
The OTX Plan B Castle Blast Shield was designed with modern AR platforms in mind.
Its compact profile minimizes unnecessary bulk while keeping weight low, making it a natural fit for lightweight and compact builds.
The blast shield is constructed from 6061 aluminum and features a durable black hard-anodized finish.
Key Features
- Plan B/Rearden-style compatible
- .9×24 taper-mount interface
- Castle-style blast shield design
- 6061 aluminum construction
- Hard-anodized black finish
- Compact, lightweight design
- Designed to redirect muzzle blast primarily forward
- Installs onto compatible muzzle devices
- Not a direct-to-barrel device
Plan B-Compatible Muzzle Devices
The OTX Plan B Castle Blast Shield is designed for compatible muzzle devices using the .9×24 Plan B/Rearden-style taper-mount interface.
This opens up a wide range of potential configurations, including compatible flash hiders, muzzle brakes, and other Plan B-style muzzle devices.
Build Your Setup
[Shop Compatible Plan B Muzzle Devices →]
We’ve also added compatible muzzle devices to our lineup so you can build a complete Plan B setup around the OTX Castle Blast Shield.
Plan B Castle vs. the Original Castle System
If you’re familiar with the original Castle blast shield, there is one important distinction to understand.
The original Castle system uses a 13/16×16 internal mounting thread.
The new OTX Plan B Castle Blast Shield uses a .9×24 Plan B/Rearden-style taper-mount interface.
These are different mounting systems and are not interchangeable.
The name “Castle” refers to the blast-shield design and the ecosystem it continues, while the Plan B version has been engineered around the mounting interface used by modern Plan B-compatible muzzle devices.
In short:
Original Castle: 13/16×16
OTX Plan B Castle: .9×24 Plan B/Rearden-style taper mount
If you have a Plan B-compatible muzzle device, make sure you’re selecting the Plan B version of the blast shield.
Designed for Real-World Shooting
The OTX Plan B Castle Blast Shield is particularly useful for shooters who spend time in situations where lateral muzzle blast is undesirable.
Consider it for:
- AR-15 pistols
- Short-barreled rifles
- Training classes
- Group shooting
- Indoor ranges
- Bench shooting
- Aggressive muzzle brakes
- Compact rifle configurations
The blast shield doesn’t replace the function of the underlying muzzle device. Instead, it gives you another way to use it.
Pair It With a Plan B-Compatible Flash Hider
One of the advantages of the Plan B mounting system is the ability to use a compatible muzzle device as the foundation for multiple configurations.
For example, pair the OTX Plan B Castle Blast Shield with a compatible 3-prong flash hider for a versatile setup that can be configured for either flash suppression or forward blast redirection.
The important part is choosing a muzzle device with the correct .9×24 Plan B/Rearden-style taper-mount interface.
Available Now from Mid State Firearms
The OTX Plan B Castle Blast Shield is now available from Mid State Firearms.
Whether you’re replacing an older Castle setup, building a new Plan B-compatible rifle, or simply want the ability to add forward blast redirection to your existing muzzle device, the new OTX Plan B Castle Blast Shield gives you another option.
[Shop the OTX Plan B Castle Blast Shield →]
[Shop Compatible Plan B Muzzle Devices →]
Important Compatibility Information
The OTX Plan B Castle Blast Shield is designed for compatible Plan B/Rearden-style muzzle devices using the .9×24 taper-mount interface.
It does not mount directly to barrel threads.
It is also not compatible with the 13/16×16 mounting interface used by the original Castle system.
Always verify compatibility with your specific muzzle device before purchasing or installing the blast shield.
The OTX Plan B Castle Blast Shield redirects muzzle blast but is not a suppressor and should not be expected to significantly reduce firearm noise. Always use appropriate hearing protection when shooting.
