Cowl Induction Muzzle Brake – Gen 1




Gen 1 Cowl Induction Muzzle Brake with matte black nitride coating. Includes shim set.

Features/Benefits –
• Our proprietary design allows for the most effective recoil reduction on most calibers (.223 up to .338)
• Recoil reduced by up to 65%
• Caliber specific brakes provide maximum performance
• Horizontal ports help to create a minimal ground signature to keep dirt and debris away from shooter
• Better on target and follow-up shots due to lack of rifle movement
• Rifle movement reduction allows for shooter to watch target penetration
• Flats are cut on the rear hex to allow the attachment to barrels with standard wrenches
• Matte black nitride coating standard, and Cerakote colors are available
• Includes shim set

6.5mm 5/8″-24 TPI
5.56mm/.223 1/2″-28 TPI
5.56mm/.223 5/8″-24 TPI
.300-.308 9/16″-24 TPI
.338 5/8″-24 TPI
.338 M18x1.5


  • Weight: 0.42 lb.
  • Material: 4140 Alloy steel
  • Outer diameter 1.10”
  • Length: 2.88”
  • *NOTE: Requires barrel to have a shoulder behind the threads to properly time the brake. Thread adapter use is not recommended or supported, and will void warranty
  • Shim thicknesses: 1-.002, 1-.003, 1-.004, 1-.008, 1-.010, 1-.015
  • Color: Black nitride. Cerakote colors are available for an additional $20.00 charge
  • Caliber and Thread Pitches Below:
6.5mm 5/8″-24 TPI
5.56mm/.223 1/2″-28 TPI
5.56mm/.223 5/8″-24 TPI
.300-.308 9/16″-24 TPI
0.338 5/8″-24 TPI
0.338 M18x1.5



18 reviews for Cowl Induction Muzzle Brake – Gen 1

  1. 5 out of 5

    I put this on my 300 winmag, Night and day difference from the seekings brake I had on it. Shoots like a 22 now! Its unbelieving how much of a difference it made. The only down fall is the price, but in my opinion well worth it if you shoot alot. I will be buying more for other rifles I have.

  2. 5 out of 5

    I forgot how well it works until I bought another rifle without . just needs to find a catchy name like fat little * **** and you might see more of these brakes out in the field

  3. 1 out of 5

    I recently purchased one of these for my Bergara rifle. There is no way you can mount this with the ports being exactly on the horizontal plane. It came with six washers of 3 different thickness. I tried every possible combination and it never came out installed correctly. They really need a better design to align this so it will function right.

    • 0 out of 5

      We’re sorry the supplied shim set did not do the trick to properly clock the CIB for you. We realized this could become an issue for some, and have a new shim set available that will be sent to you and should fix the problem.

  4. 5 out of 5

    Great brake – great customer service. really brings down the recoil of the 338. i have other breaks and this is my favorite. very easy to install and great finish.

  5. 5 out of 5

    Great Brake – Have 4 of them BUT the shims provided do not allow you to time it. Need more various thickness shims!

    • 0 out of 5

      Jeff, we’ll send you out a set of our new shims that have a better variety of thicknesses and make it easier to clock the CIB properly. Please let us know how else we can help.

  6. 5 out of 5

    As others have noted, the shim set is a bit lacking, but I figured that I’d just use a peel washer. My biggest actual complaint is the printing on it. The large main part of the print is offset, giving the optical illusion that the muzzle break is not timed correctly even when it is. This has no affect on function and would not be a determining factor in me getting another one, but my OCD is still unhappy about it. Im still debating whether to install it with the logo down, to avoid this. Otherwise, it appears to be an excellent product.

    • 0 out of 5

      Thank you for bringing this to our attention. We are always looking for suggestions for improvement, and will review this on the next run of Gen 1 CIBs.

  7. 5 out of 5

    Bought this and put it on my 6 lb 300 Win mag. I did not have any of the shim issues the previous reviewers had my came with a complete set and the 3rd one I tried worked perfectly.
    took it to the range and it kicks less than my 10 lb AR-10. I am super impressed and really happy with it. Its worth the money for sure. its the best brake on the market that does not need to be gunsmith installed.

  8. 5 out of 5

    OK – Just installed my 5th brake on a 6.5 CM with the extra shim kit. Works like a charm! Now it takes 5 minutes to time and it is much easier. Thanks for the shims!

  9. 5 out of 5

    I have 4 of these brakes with 2 more on the way. Most brakes are of poor design and just don’t do much with recoil. This CIB truly offers one of the best reduction in felt recoil to the shooter.

  10. 5 out of 5

    The 6.5CM is not a heavy recoiler in my Savage 10 FCP-SR. Even so, looking to the future after having strong side shoulder surgery, I wanted to get a good muzzle brake. After extensive research, I settled on the ZRODELTA CIB in the subject caliber. By the time the Doc released me to shoot, I had received and test installed the brake. I received the old shim pack with mine and could not get it to time correctly. After speaking with Chris and getting the updated shim pack, I was able to properly install the CIB. Two months after surgery, the Doc released me to shoot. At the range, I first removed the brake just to see what it would be like without it. Not only was it uncomfortable, it hurt. I then installed the CIB and shot. What a difference! This thing reduced the recoil impulse so significantly, it went from being painful to shoot to very comfortable. Although I can’t measure it, I would be willing to bet the recoil impulse was reduce by at least 50%. OK, I am shooting again. But would the brake affect my accuracy? Absolutely not! This was a .25 MOA rifle before the surgery. It still is today, with the brake installed. BZ to everyone at ZRODELTA for making an effective brake that, at least for me, did not impact accuracy.

  11. 1 out of 5

    to Support:
    Thanks for responding to my problem with the shim set that came with my brake, but a month has passed by and I still haven’t received a new set of shims that you said I would be getting.

    • 0 out of 5

      Just saw your message and unfortunately this fell through the cracks. Chris is sending your shim set tomorrow.

  12. 5 out of 5

    Thank you for sending me a new shim pack. I have it aligned perfect now and it works great!

  13. 5 out of 5

    Put one of these on a mark v 300 wby mag that I had a friend thread. (Number 2 profile barrel) and first trip to the range I put 30 rounds through the rifle. Only stopped short of putting both boxes through it because it’s all I had. No flinch, no pink shoulder, no sore spot. I kept having to slow myself down and let the barrel cool because it was just so damn easy to load and burn another 3 rounds. In my experience the zero delta brake makes my 300 weatherby mag plinking comfortable with 180 grain ammo. The product has more than proven itself to me and anybody else that shoots my rifle.

  14. 1 out of 5

    I recently purchased a ZRODELTA CIB to replace the A2 flash hider installed on my new PSA PA-6.5 by Palmetto State Armory. The barrel profile is heavy, but the end near the threads has a slightly thinner contour. Please find the PSA specs below. The included shim kit does not appear to work with the barrel contour of the PSA 6.5. The shim just flexed back over the barrel because there wasn’t enough barrel lip to hold the shim. I called ZRODELTA and spoke with Justin about the issue. He said he would need to check with engineering and then get back in touch with me. I look forward to hearing back from ZRODELTA and hopefully finding a way to install the CIB. Thank you.


    SKU: 516447017
    UPC: 516447017
    MFR#: 516447017
    Barrel Length: 20″
    Gas System: Rifle-Length
    Barrel Profile: Heavy
    Barrel Steel: 416R Stainless Steel
    Barrel Finish: Stainless
    Chrome Lining: None
    Muzzle Thread: 5/8-24
    Chamber: 6.5 Creedmoor
    Twist Rate: 1:8
    Barrel Extension: M4-style
    Diameter at Gas Block: .750
    Gas Block Type: Low-profile gas block
    Muzzle Device: A2 Style Flash Hider
    Receiver Material: Forged 7075 T6
    Receiver Type: PA10
    Handguard Type: PSA 15″ Lightweight M-Lok Free Float Rail
    Bolt Carrier Group Included: Yes, PA-10 BCG
    Charging Handle Included: Yes

    Barrel: 20″ Heavy 416R Stainless Steel, chambered in 6.5 Creedmoor with a 1:8 twist rate and rifle-length gas system. Upper is paired with a Palmetto State Armory 15″ Lightweight M-Lok free-float rail, low profile gas block, and an A2-style muzzle device.

  15. 5 out of 5

    I purchased the CIB for my Tikka T3X Lite in 300 Win Mag. I had the barrel threaded and timed to the brake so the ports are perfectly horizontal. This rifle with 200gr bullets kicks less than my Remington 700 SPS with 130gr bullets. Muzzle jump is minimal. Dust kick up in the prone position is minimal. Accuracy is excellent, 1000 yards benched and 500yds in field positions are no problem. My best group to date is .25MOA at 200yds with factory ammo. It makes the 300 a joy to shoot. After researching several brakes, I am glad I settled on the CIB.

  16. 2 out of 5

    I just got one of these in 6.5 mm for a 6.5 Grendel build. Unfortunately, the outside diameter of the shims is larger than the recessed area at the back of the brake and larger than the shoulder behind the threads on my barrel. If I try to use the shims to time the brake, the shoulder of the barrel pushes the inside edge of the shims into the recessed area and pushes the outside edge of the shims away from the back of the brake. Why would you ship shims with an outside diameter greater than the inside diameter of the recessed area on the back of the brake? I’m going to see if I can find a crush washer of high-temperature o-ring to make it work. If that doesn’t work, I’ll see if I can sell it to someone else.

    • 0 out of 5

      Hi Dante,
      It sounds like your barrel does not have a shoulder for the CIB to mate to so it can be properly clocked. Our shims are designed to fit the flat on the back of the CIB and not inside the threaded portion of the brake, so it may not work for this particular barrel. Please contact our customer service department directly for an RMA# to return the brake and receive a credit.

  17. 4 out of 5

    Update to my previous posts: I was able to time the CIB to my 6.5 with the shim kit I purchased from PWS. PWS provides a thick starter shim with their kit. The brake is fantastic. My only complaint is ZRODELTA customer service is nonexistent. They never called me back or responded to emails. I would probably buy another CIB from them for my precision long range rifle, but I am hesistatant to do so based on my recent experience. I hope to hear from them in the near future.

    • 0 out of 5

      Hi Michael
      Your experience with our Customer Service is certainly not what we strive to achieve and is not typical for us. My sincere apologies to you, and we would appreciate an opportunity to meet your expectations should you choose ZRODelta again. Thank you for your business and your honesty.

  18. 5 out of 5

    Never bought a muzzle break so don’t know anything about them. I want to put one on my 6.5. My question is what’s the “clocking” ? Does this mean proper alignment with the barrel to make it work correctly or what.

    • 0 out of 5

      Clocking refers to the proper alignment of the ports on the CIB to the 9 & 3 o’clock positions. This redirects the escaping gases to the right and left of the shooter when properly installed, and eliminates any ground signature in the prone position. For the Gen 2 CIB, the flat of the brake will be aligned with the top of your barrel.

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