RE: Mark V vs Vanguard Weatherby
No, the accubrake does absaolutely nothing to improve or degrade the ballistics of the bullet.
What the accubrake does is reduce recoil when the gasses from the powder push against the holes in the brake and it increase muzzle blast and noise due to the gasses and sound waves being redirected from traveling away from the shooter to traveling to the side and back.