Plan B-Compatible Castle-Style Blast Shield
The OTX Plan B Castle Blast Shield by Mid State Firearms is a compact, lightweight blast shield designed for compatible Plan B/Rearden-style muzzle devices.
The Castle-style blast shield design provides forward blast redirection while maintaining a compact profile and low overall weight. It can be installed when reduced lateral muzzle blast and concussion are desired, or removed when you want to run your muzzle device without the blast shield. Retains the same outer dimensions as the OTx / Breek Castle Blast Shields, but with internal threads compatible with Plan B muzzle devices.
IMPORTANT: This is the Plan B version of the OTX Castle Blast Shield. It uses a .9×24 Plan B/Rearden-style taper-mount interface. It is not compatible with the 13/16×16 mounting interface used by the original Castle system.
Plan B-Compatible Castle Blast Shield
If you’re looking for a Plan B Castle blast shield, the OTX Plan B Castle Blast Shield provides the familiar Castle-style blast-shield configuration with a mounting interface designed for compatible Plan B/Rearden-style muzzle devices.
The .9×24 threaded taper mount connects the blast shield to the compatible muzzle device, allowing the shield to be installed or removed as needed.
This makes it a convenient option for shooters who already use compatible Plan B-style muzzle devices and want the ability to add forward blast redirection without replacing their muzzle device.
Compatible Plan B Muzzle Devices
The OTX Plan B Castle Blast Shield is compatible with select muzzle devices using the .9×24 Plan B/Rearden-style taper-mount interface.
Build Your OTX Plan B Setup
[View Compatible Plan B Muzzle Devices →]
Browse our compatible muzzle devices to find the right host for your OTX Plan B Castle Blast Shield.
Compatibility Note: Verify that your muzzle device uses the compatible Plan B / .9×24 taper-mount interface before purchasing.
Reduce Side Blast and Concussion
Muzzle brakes and compensators can provide excellent recoil control, but they can also produce substantial lateral blast and concussion.
The OTX Plan B Castle Blast Shield surrounds the compatible muzzle device and redirects muzzle gases and blast primarily forward.
This can be useful for:
- AR-15 pistols
- Short-barreled rifles
- Training classes
- Team shooting environments
- Indoor or partially enclosed ranges
- Rifles using aggressive muzzle brakes
- Situations where reduced lateral blast is desirable
- THIS IS NOT A SUPPRESSOR AND DOES NOT SILENCE OR REDUCE NOISE
Install the blast shield when forward blast redirection is preferred, or remove it when you want to run your muzzle device normally.
Slim, Lightweight Design
The OTX Plan B Castle Blast Shield provides blast redirection without adding unnecessary bulk.
Key Features
- Plan B-compatible
- .9×24 mounting thread
- Plan B/Rearden-style taper mount
- Compact Castle-style design
- Lightweight construction
- Durable black hard-anodized finish
- Quick installation and removal
- Designed to redirect muzzle blast primarily forward
Plan B Castle vs. Original Castle System
There are two different mounting systems that use the Castle-style blast-shield concept.
The original OTX/Breek Castle system uses a 13/16×16 internal thread and mounts to compatible outside-threaded Castle muzzle devices.
This OTX Plan B Castle Blast Shield uses a .9×24 thread with a Plan B/Rearden-style taper-mount interface and mounts to compatible Plan B-style muzzle devices.
Do Not Confuse the Two Systems
Original Castle: 13/16×16
OTX Plan B Castle: .9×24 Plan B/Rearden-style taper mount
These are different mounting systems and are not interchangeable.
If you have an original 13/16×16 Castle-compatible muzzle device, this Plan B version is not the correct blast shield. You want the OTx Blast Shield instead.
Not a Direct-to-Barrel Blast Shield
The OTX Plan B Castle Blast Shield does not thread directly onto your barrel.
It mounts to a compatible muzzle device.
Installation Configuration
Barrel → Compatible Muzzle Device → OTX Plan B Castle Blast Shield
The barrel’s muzzle thread and the blast shield’s mounting thread are separate interfaces.
A compatible muzzle device may attach to the barrel using a common barrel thread such as 1/2×28 or 5/8×24, while the blast shield attaches to the muzzle device using the .9×24 Plan B/Rearden-style taper mount.
Specifications
| Specification | Details |
|---|---|
| Manufacturer | Mid State Firearms |
| Product Line | OTX |
| Product Type | Castle Blast Shield |
| Material | 6061 Aluminum |
| Finish | Hard Anodized |
| Mounting Thread | .9×24 |
| Mounting Interface | Plan B/Rearden-style Taper Mount |
| Direct Barrel Mount | No |
Frequently Asked Questions
What is the OTX Plan B Castle Blast Shield?
It is a Castle-style blast shield designed to mount to compatible Plan B/Rearden-style muzzle devices using a .9×24 taper-mount interface.
Is this the same as the original Castle blast shield?
No. The original Castle blast shield uses a 13/16×16 internal thread. The OTX Plan B Castle Blast Shield uses the .9×24 Plan B/Rearden-style taper mount.
Why is it called a Castle blast shield?
“Castle” refers to the compact blast-shield design and its relationship to the Castle-style blast-shield ecosystem. This Plan B version uses a different mounting interface from the original 13/16×16 Castle system.
What muzzle devices does it fit?
It fits compatible Plan B/Rearden-style muzzle devices using the .9×24 taper-mount interface.
Is it compatible with 13/16×16 Castle muzzle devices?
No. The original Castle system and the Plan B version use different mounting interfaces.
Does it thread directly onto my barrel?
No. It attaches to a compatible muzzle device.
Does it reduce recoil?
The blast shield is designed primarily for blast redirection, not recoil reduction. The recoil characteristics come from the underlying muzzle device.
Does it make the firearm quieter?
No. It redirects muzzle blast but is not a suppressor and should not be expected to significantly reduce firearm noise.
Will it fit inside my handguard?
Check the outside diameter of the blast shield against the internal diameter of your handguard before installation. Adequate clearance must be maintained.
Can I use it with any Plan B muzzle device?
Only if the muzzle device uses the Plan B compatible .9×24 taper-mount interface. Verify compatibility before installation.
Important Safety Information
The OTX Plan B Castle Blast Shield redirects muzzle blast but does not make a firearm hearing safe and is not a sound suppressor. Follow all applicable NFA rules if looking into suppressors.
Always use appropriate hearing protection when shooting.
Ensure the blast shield is properly installed on a compatible muzzle device before firing. Do not modify the mounting interface or use the blast shield with an incompatible muzzle device.
-300x300.png "15' Gen1 Free Float Quad Rail, photo")
sound of freedom – This was a great set up. I loved being able to customize the set up. Only issue I had was my own fault as a newb to building these. I used a heavy barrel in a slim hand guard. It makes adding attachments tough with clearances. Hoping someday to also get an AR10 from here.