Ported barrel stovepipes?

[bulls-i]

Hi guys,
I have an M&P 9mm 5” Pro. Had the gun a long time & put a lot of rounds thru it. Never a problem.

Decided to put a red dot on it. Couldn’t find a kit so bought all the parts individually: ported slide, ported barrel, Holosun red dot & mounting plates.

First shot it with the non-ported barrel & it worked great as usual.

Put on the ported barrel & was getting 1-2 stovepipes/failure to eject every magazine?

Same ammo as I’ve always used – 115 FMJ Blazer.

Asked the range officer & he said getting too much gas bleed off with ported barrel. Either go back to non-ported barrel or shoot hotter loads.

Does this sound right?

Thanks

 

[ShieldDriver]

Not no expert but I'm thinking you changed the slide mass and your recoil spring isn't correct for that configuration. Probably just need to find the right spring combo and it should work fine.

I'm curious what the velocity differences are between the ported and non ported barrel. Anyone ever chrono them?

 

[mscampbell2734]

Combination of heavier then standard slide, normal MP slide is 4 1/4, plus optic, and porting, is resulting in sluggish slide travel.

Either hotter loads or reduced recoil spring.

 

[bulls-i]

normal MP slide is 4 1/4"

.

True the full size M&P is 4-1/4", but I have an M&P Pro & they have a 5" slide.

 

[Saudade]

My 5" ported with RMR works fine with the standard rsa. I did put in new one when I swapped out my 4.25" slide for the ported one.

Can't say I recall shooting Blazer 115s, but I did shoot some WWB and Federal 115s on my last outing with no issue.

So try some other ammo, another magazine, make sure it's lubed properly.

 

[Ranger17]

My only ported model was a Shield so with a shorter barrel. But all i ever shoot in any of my 9’s would be 115gn and never had an issue whether ported or std MP’s.
Only ammo “issue” i ran into is some brands including Blazer say no to ported barrel use. From what they told me, due to some ammo brands having thin plating that can flake off. I am sure not everyone follows those recommendations and I doubt that could have any affect on stovepipes.

 

[mmb617]

Not no expert but I'm thinking you changed the slide mass and your recoil spring isn't correct for that configuration. Probably just need to find the right spring combo and it should work fine.

I'm curious what the velocity differences are between the ported and non ported barrel. Anyone ever chrono them?

I'm not an expert either but I think your analysis is probably correct.

I don't see the "hotness" of the loads being the issue. We took my son's new Shield Plus PC to the range today and had zero issues with it. We were shooting my reloads which are loaded on the light side, but it fed, fired and ejected them fine.

On the way home we got to discussing how much difference in velocity a ported barrel would make and decided to take the chrono next trip. I have a 1.0 Shield 9 for comparison purposes. We'll shoot the same ammo through both and see what effect the barrel porting has.

 

[uncleted327]

I wouldn't seek out that range officer for any further assistance. I haven't owned any S&W ported guns but I've owned C model Glocks in 40, 9, and 357 Sig and the difference between ported and unported is not that significant. Certainly not enough to cause that type of failure. He probably thinks you'll burst into flames if you shoot it too close to your body or burn your eyebrows off too.

 

[bulls-i]

Took all the parts (frame, both barrels, both slides, spring) to a gunsmith to get checked out. According to him, "Performance Center" ported barrels & slides need to be matched together. As I said in my original post, I bought mine separately. Hope he is right. Guess I'll find out in a few weeks.