I've only installed 1 Vias brake, on a 300 RUM. I didn't get the chance to test this one. I've installed 3 KDF brakes. One on a 270 Win, which was very effective in reducing recoil. Another on a Remington Model 7 in 243 Win; this one felt like a 22 LR but the muzzle blast was really bad. Both of the above KDF's were same diameter as barrel. I did install a large KDF on a 458 Win Mag and really could not tell any difference in recoil, brake on or off. If there was any reduction in recoil, it was not much.
George