Complex sentence: The barrel is threaded to accept a suppressor, which worked by reducing the discharge's sound, without attempting to reduce the velocity of the bullet or rather stops air from rushing into the barrel, inhibiting the sonic signature.
Split into simpler sentences: The barrel is threaded to accept a suppressor, which worked by reducing the discharge's sound, without attempting to reduce the velocity of the bullet. Or rather stops air from rushing into the barrel, inhibiting the sonic signature.