Porting generally reduces muzzle jump...especially in a fixed frame gun like a revolver. Its a debate on whether it affects recoil or not...personally, I think it does not...
I have fired a couple of 1911's that were ported...( I think in 4" or 4.25" )...and yes, I did get more gas back towards my face and it was a little distracting ....same thing on a couple of 1911's with compensators. On a semi auto the reduction of muzzle jump is less than a revolver ...and I agree with the post that said it may slow the bullet a little...
I shoot 1911's all the time in a 5" ...no porting or compensators in .45acp and 9mm.../ my primary competition gun & carry gun is a 5" in 9mm.../..I like the balance, sight plane, feel & weight of a steel 5" gun / its what I am used to... and in my late 60's, I have considered going to a 1911 for carry in a 4.25", but I don't want an alloy frame so its only 4oz or so lighter --- and at 6'5" and 290 lbs ....will I really notice 4oz, or even 8oz...No.. I have stayed with a 5" gun...because I just shoot them a lot better than a 4" or 4.25"...
But if I wanted a 3 1/2" 1911, I would be concerned about muzzle jump slowing down my follow up shots... / ... so I might consider porting ...and just deal with the distraction....but only if I really wanted that 3 1/2" gun....
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I own a variety of browning shotguns with ported barrels ...and it really reduces muzzle jump in 12ga and 20ga. I like it in shotguns..but that is very different on 9 lb guns in 30" barrels. The only ported revolver I own is a 3" S&W in .44 Mag. Its an RSR gun, the Trail Boss, a 629 model...and the porting makes it easier to shoot by reducing some muzzle jump...but the gas & noise is big time distracting with full power loads ...