Back in the early 70s, I sent a S&W 29 to Larry Kelly to have it cut to 5", action job, hard chrome, and magnaported -- I shot that gun a bunch, and ended up trading it off, much to my regret.
Currently have a Magnaported 6" Freedom Arms .475 LB that I bought used -- one of my favorites. Also have a 4" S&W 329 that is NOT ported. My daughter says the unported 329 is much louder than the ported .475.
Recently picked up a second 6" Freedom Arms .475. It is exactly the same as the aforementioned ported version. With the exact same load, exact same front sight, exact same rear sight setting (bottomed out), exact same hold, the ported gun shoots to a lower point of impact vs. the unported gun. Some evidence suggests that ported guns show a loss in velocity, so the faster unported gun should shoot lower -- but it doesn't. I know, no matter how much the same guns are, they are different.
Here are some snippets from an article by Paco Kelly (no relation to Larry Kelly of Magnaport fame), who has actually used a magnaported firearm to defend his life.
"44 magnums has been in and out of my life. A model 29 S&W that was custom rebuilt by Larry Kelly of Mag-Na-Port fame in the late 1970s save my life one dark and deadly night on a bayou bridge in Louisiana. Kelly had cut the barrel to three plus inches, round butted the grips to the K-Frame round butt size and fitted it with neoprene grips of the times...slicked and tuned and timed and of course mag-na-ported. When it was fired at night it was like the electric company lighting the night..................
My main carry gun was of course, my famous and somewhat infamous, S&W mod.29 44 magnum...cut to three inch barrel, and Mag-N-Ported, with the grip cut to the Mod. 19 round butt. I carried it in an upside down shoulder holster...it was fast to get into action, extremely powerful...and for me put the stories I hear about muzzle flash blinding you at night, and recoil making the second shot take too long, and a lot of other stuff I read...just that for me B.S. and untried magazine material.
I never had any of those problems....I fired it in several night time situations without the dreaded "blindness" from muzzle flash....it saved my life in a car one terrible night when I fired it twice...with no recoil slowness problems or blindness. The two individuals that could testify to that directly, unfortunately for them, are too busy reaping their reward for misspent lives in another world, to answer any questions.
Not that the baby beast didn’t give off a horrible roar and a good deal of muzzle flash. It did! But the flash was always too short in time, to blind. And the muzzle blast I found, was great because it scared the hell out of my adversaries. My ammo was Winchester’s famous commercial loading that had a gilded lead Keith type 240 grain bullet doing about 1100 fps from the short barrel. Like a big fist with a 640 lb punch!"
Special Handguns
Read the whole article, I think you'll like it.
I wouldn't let porting deter me from buying a gun I wanted, but probably wouldn't have it done to a gun I already owned -- except maybe that 329.
FWIW,
Paul