I'm going to break in part with the answers thus far. I have had a ported and a non-ported Shield in 9mm, and this is my opinion based on researching the question for myself and now owning a Performance Center ported M&P9 M2.0 Shield, but before I get started, I am not interested in debating this with others as it is merely my opinion, and more so that of Jerry Miculek as I will discuss, so others are free to have their own opinions.
First, before I address .45 ACP specifically, yes, porting works, but the differences are going to depend on the shooter for a variety of reasons that I will briefly discuss, and everyone as you know is different. You can ask a bunch of people like me and others on here who've owned both, and you will get different answers and that's not necessarily due to a variation in competence, but everyone has different biomechanics, shooting experience, expectations, etc.
I used to hazard a guess that the answer to the porting question was as simple as saying it helps people who don't shoot a lot (let's say people who don't shoot weekly, monthly, or even quarterly), but Jerry Miculek has changed my mind slightly about that.
Jerry ports all this guns whenever possible (he's not exactly going to ruin a vintang 1911), but he even ports all his concealed carry guns. If he doesn't get the gun ported, he has it Magnaported:
https://magnaport.com/
He claims it reduces perceived recoil by up to 30% or even 40% and he does NOT feel it is only an advantage in competitive shooting ([ame]https://www.youtube.com/watch?v=Q6dWDFcoFFs[/ame]). In the video I just shared, he cites 40%. In others I've heard him say 30%. I think he said 40% in this video because he is specifically discussing quadra porting where he not only has four lightening cuts in his slide (like my Shield), but he also has four ports in the barrel (unlike my Shield which only has two). That's only a guess on my part because I don't remember him ever saying anything specifically one way or another, but he does go between 30% and 40%.
Before I move on, let me address two obvious things that come to mind. One, I have no idea if he is sponsored by Mag-na-port International or if he pays to get his guns ported (or if Smith quadra-ports his guns). Moreover, I can't tell you what's in Jerry Miculek's heart, so even when/if he does have a personal interest in recommending Mag-na-porting, porting by Smith & Wesson (because he is endorsed by them and others obviously), or something else (like Mossberg products), I can't tell you if he's prone to lying or exaggerating the importance of it or not. At the very least, however, it should be taken as a bias (whether mild or otherwise). I'll get back to Jerry more in a moment.
On the other side of the argument are certain people like Nutnfancy, for example (I'm not picking on him, but he just readily comes to mind), who dismiss differences in muzzle flip generally until he changes his mind (e.g. see videos where he discusses the 4" PPQ until he tests a 5"). Others like Sootch00, however, swear by the porting of the 9mm Shield (and he
is biased in favor selling guns
in my opinion).
A more moderate opinion, yet again, in my opinion, would be Mrgunsngear (
https://youtu.be/1A0RpB72WC0). When he reviewed my gun in particular I paid close attention to what he had to say before I bought it because I have watched him since he started his channel long before most heard of him and I trust most of what he says (though what he said about Beretta's "Stellium" barrel design sounds suspiciously like Browning's back-bored technology which has been around for decades now even on their pump guns. You'll know what I mean if you watch where I saved the video and read about back-bored technology from Browning). Nonetheless, we are all guilty of making mistakes and he is nevertheless one of the better people to listen to in my opinion (along with Massad Ayoob and a few others).
Mrgunsngear essentially said the "pro's" of porting are that 1) yes, it gives "a touch—a touch—less recoil" (repeating the word to emphasize it), and 2) "the muzzle rise is a "touch less as well", and he recommends watching competitive shooter Julie Golob's slow motion video comparing her shooting a ported vs non ported Shield which is hard to gauge because of the editing (the bottom of her fist is not always in the same place so I attempted to use masking tape to keep track it).
Two things about that, first, Julie, as most people on here probably know, is sponsored by S&W as well, and second, as Mrgunsngear points out, it's only a "touch less" (I think), it wouldn't be the first time I could barely
see a difference (if I saw one at all) only to hear the shooter claim there was a significant difference. That can either be because of bias, or it can also be from the reality that people are often strong enough shooters to mitigate the muzzle flip but that does not imply they are not working at least slightly harder to do it. Bias can also cause the opposite to be true.
Mrgunsngear also said that for most people, "it is almost imperceivable". Honestly, I have no way of verifying that, and scientifically speaking, neither does he (though I know he likely has at least sought opinions anecdotally from his wife and others to form his opinion). My guess is that other biases probably come into play more, such as what you own. I think most people who bought a ported barrel will tell you it's worth it as a sort of way to validate their purchase after the fact, and those who haven't owned a ported version often tell you it's not worth it to make themselves feel better about not having that feature (though certainly there are many exceptions in both cases).
Mike (Mrgunsngear) also said there are two downsides that are true. It's louder (it is), and there is a slight risk of getting debri from the gun in your eyes (anything from burnt or unspent powder to metal shavings). Regarding the volume, I personally would not worry about it. I made the mistake of firing a gun without my ears on in close quarters, and I was firing a .357 SIG with a bullet traveling 2100 fps while standing next to a wall. Most people are only going to shoot their guns with ear protection on, but if you make a mistake like I did, it's not the end of the world. My left ear rang for two days because it was facing a wall by only a couple of feet, but my right ear didn't ring at all. As long as you're generally safe about practicing, this isn't a concern in my opinion (i.e. I always wear both electronic over-the-ear and spongy in-ear protection). If you have the remote chance of getting in a gunfight, you won't notice a difference in volume between ported and non-ported (and will have much more to worry about.
Regarding debris getting into one's eyes shooting from retention, for example, I agree it is a real possibility but I also agree with Mrgunsngear that it is such a remote possibility I wouldn't worry about it. Again, you'll be wearing protection when you practice and the chances of getting in a gunfight are slim, and the chances of getting in a gunfight and shooting from retention is even slimmer, and the chance of getting into a gunfight, shooting from retention, and then getting debris in your eyes becomes almost nonexistent. Nonetheless, here's a cool video from Mythbusters that lets you see what I am talking about regarding debris though it is not specifically addressing the porting issue, but you can see two things: 1) it is not always coming out the front or even from porting, and 2) the gun they are shooting is not ported ([ame]https://www.youtube.com/watch?v=7y9apnbI6GA[/ame]). I'm sharing this video because, even though I don't worry about it, I don't have the right to tell anyone else not to. Caveat emptor.
There is another downside. The pistol will get dirtier so it's harder to clean, but that boils down to the individual. I do recommend people take greater precautions cleaning their guns ported or not. Use gloves because, again, in my opinion, I am personally persuaded that the studies that show the harm of lead gun cleaning agents are worse than people realize, but I don't want to go off in a tangent about it.
Getting back to Jerry Miculek. His opinion is that he ports his carry guns because he wants to "cheat" and afford himself every advantage possible in a gunfight to send as many rounds down range as quickly as possible. If Jerry Miculek, one of the world's fastest shooters that ever lived, thinks porting has an advantage, it should at least give pause (keeping in mind what I said earlier). But to say you should just because Miculek does would be an appeal to authority. What I will say is that the data I've seen suggests you should put no fewer than three rounds on target to stop someone on average (more if you're not hitting center of mass). If you've watched a lot of real world gunfights on video, you know sometimes there isn't much time, which means you're going to want to shoot like a competitive shooter. It's vogue to say these things only matter in a match, but reality seems to suggest that time is of the essence when you're fighting for your life. People worry about single handed reloads and what not, but I think the more important aspect is getting that first round off and what is going to happen with those first few rounds (which is why I'm fine carrying 7+1) in a Shield which I personally can control better than a P365 or Hellcat.
Anyway, a little over a year ago Jerry Miculek said he upgraded his old carry gun, an M&P9c, to a M&P9 M2.0 Compact 3.6". I don't think his old gun was quadra-parted, but it was ported (and he also had crimson trace laser grips which I thought was interesting). He said he is having his new gun "mag-na-ported". As an aside, he was also adding HiViz Litewave 3 sights (sounded like an endorsement perk to me, but one way or the other, he did have them on his old gun as well), and although it didn't sound like he was replacing the M&P trigger per se, he was going to work on it to bring it down to about 4 lbs. where he says he likes it. For those interested, he also carries the FBI's new Hornady 135 gr. FlexLock rounds (
https://press.hornady.com/release/2018/04/26/hornady-awarded-fbi-9mmp-service-ammunition-contract/). Lastly, he freely admitted he's sponsored by Hornady, and he also had been carrying this round for a couple of years before the FBI adopted it.
Anyway, my personal opinion researching and owning a ported gun (and the unported version of it) is that I prefer porting, I think it does help marginally, but not enough to make it a priority. In other words, if I can spend $50 or $100 tops over a base model for
basic a ported PC version, I will do it every time (because I will also get a shorter reset if I don't want to spend the Money on an Apex trigger). And this is what I did for my Shield. However, if porting is not available, I have no problem buying an M&P Shield without it, even a 4" PC model, and I don't necessarily see myself paying for it after the fact. I have a slew of guns that need other things (optics, night sights, in one case a trigger, and so on), so I will take care of all those things first, and if at some point I don't have anything new in need of more important upgrades or other changes, I might pay to port a smaller gun I carry a lot (that would benefit the most), but again, it's not a high priority and if I never get to it it's not a big deal for me. If I buy a .45 Shield, I will attempt to get one that is ported even though .45 ACP's may not benefit as much as say a .40 or even 9mm +P, but currently they don't port the specific model I am interested in, so if that doesn't change when I am ready to buy it, I probably won't port it, but I certainly wouldn't talk anyone out of it, even if they just like the way it looks.
In fact, it does look cool, so if someone wants the coolness factor, I'd rather pay for porting a pistol and getting some utility out of it (imagined or otherwise) than say cerakoting one of my ARs, but that's just me.
Everyone's personal preferences are valid on this point which is why I am not going to debate it. Porting won't seem to make a difference for some, it will make a difference for others, but most gains will be marginal so do what your heart wants as long as you can afford it. As someone mentioned, it might be a better idea to sell or trade and repurchase the PC version (which will have the shorter reset if you don't plan on getting an Apex trigger), but that also depends on the laws in your state. If you can't freely buy and trade firearms from your neighbors like I can and do often, I would not suggest selling or upgrading it at a gunshop unless you feel like taking a bath.
Lastly, I apologize for the long post, but I am home sick and am board as hell until my wife gets off the phone.
