Since we’ve come out with the 6.5mm Ultra 7 and 9, several people have asked us if we offer a 6.5mm-specific CB Brake to match. The answer is no. Here’s why.
A few months ago, I had the opportunity to help Cal Zant with his comprehensive Comprehensive scientific review of precision rifle muzzle brakes. One of the specific results he found was that the difference in recoil reduction on 6.5 mm from a .30 cal to 6.5 mm cal aperture was about 1-3%:
I ran tests to see how much it mattered if a muzzle brake was caliber-specific, and those results were also surprising. I tested the effectiveness of having a caliber-specific brake on 4 very different muzzle brake designs that I had in all calibers: the APA Little B*, Holland 1.25” Radial QD Brake, Impact Precision Brake, and West Texas Ordnance Brake. I only found an improvement of 1-3% if a brake was 6mm rather than 30 caliber (7.62mm).
To be clear, I tried the 6mm, 6.5mm, and 30 caliber brakes all on the 6XC, and in all 4 muzzle brake designs, there was only a difference of 1-3% in recoil reduction in terms of both overall momentum and peak force. That surprised me. I expected the caliber size of the bullet hole in the brake to make more of a difference. But, that’s why I actually run the tests and don’t just talk about this stuff!
In our application, that 1-3% of difference in recoil reduction would only be applicable when the suppressor was not mounted. Here is a tech note that that effect.
With the suppressor mounted over the brake, the 6.5mm-specific suppressor baffle apertures capture as much gas as possible to give the additional suppression. That’s the part that makes a 6.5mm Ultra 7 about the same dB as a .30 cal Ultra 9 when shot on a .260 Rem or 6.5 Creedmoor.
Based on this, we do not offer a separate “6.5mm” CB brake at this time.
If you have any questions, please do not hesitate to give us a call or shoot us an email.