I don't doubt that porting works, it's just a matter of how much and do you want to put up with the noise and the aesthetics.
Online recoil calculators seem to give too much value to free recoil effects of the powder gasses since they assume a large value for powder gas velocity.
The SAAMI formula for recoil uses a lower and likely more accurate value for gas velocity.
Working with the formula, if we could eliminate the free recoil effect of the gas entirely we would reduce recoil by about 13%, using their example of a heavy hunting load and a 7 pound gun.
That would be significant, but also impossible since we can't vent all the powder gas to the side and up. How much we can vent off is anybody's guess. It would make a good experiment.
