.40 Shield Kaboom

[Rastoff]

Rastoff,

After reading your post I took a picture to compare three barrels from my guns

The 40 Shield has obvious machining done to it. To me it looks like it started out similar to the compact barrels and then was honed or bored out.

Thank you for that picture. The more I look at these, the more confused I get. It appears that the Shield feed ramp is milled out a little more. This doesn't seem to be a defect, but intentional. I wonder if the Shield has trouble feeding rounds in a normal chamber/feed ramp set up?

Could you take a picture of your Shield barrel with a round inserted in the chamber please? I want to see if the round is not supported as well as the others.

 

[Russo2]

Tried to get the best pictures I could with my phone camera. Lighting was terrible

 

[pibulloncrack]

My Shield, on the right, looks just like Russo2's. I also included the compact 40 to compare. The more I look at the two side by side the more this concerns me.

 

[Jakpro]

Personally, I find that comparison photo very concerning. I have a Shield .40 and am increasingly wondering when it will blow???

 

[feelinlucky]

The unsupported chamber area adjacent to the feed ramp is a common part of almost any semi-auto pistol.
This is a Kahr PM40.

This is a Gen 4 Glock 17.

This is my 40 Shield.

 

[feelinlucky]

Personally, I find that comparison photo very concerning. I have a Shield .40 and am increasingly wondering when it will blow???

Wanna sell it?

 

[Jakpro]

Wanna sell it?

I am seriously thinking about selling it.

 

[Scott E White]

I am seriously thinking about selling it.

Post it up at a fair price, and it won't last long!

 

[OakleyFreak]

9mm Shield with 50 rounds run thru it

 

[modraker]

I am seriously thinking about selling it.

Mine's going into hibernation until the kaboom issue is settled. I like the Shield too much to sell it. Besides, I "sweated blood" taking out the original sights so I can put in Ameriglo night sights. Meanwhile my EDC will be a Kahr CM9 with the built-in kaboom panel.

 

[Russo2]

9mm Shield with 50 rounds run thru it

Looks basically the same as all the 40 barrels. Hmm.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

 

[Roger S&W]

Wanna sell it?

My M&P Shield 40 is brand new, never fired. I'll sell it for $375 shipped to your FFL. Also have 2 extra 6 round magazines.
Anybody interested. First "I'll take it" via PM gets it.

 

[Rastoff]

My Shield, on the right, looks just like Russo2's. I also included the compact 40 to compare. The more I look at the two side by side the more this concerns me.

Thanks for the comparison pic. It appears painfully obvious, especially as more people post pics, that this is an intentional design by S&W. It also concerns me that they've taken this path. The Shield chamber is clearly not fully supported. For the 9mm this might not be as much of a concern, but for the .40S&W it really concerns me, because it generates so much more pressure.

This also changes my entire thought process on this "kaboom" issue. Now I'm thinking that neither this one nor 2001gmc's were out-of-battery failures, but simple case ruptures due to an unsupported chamber. With what I'm seeing in the pictures, the rounds don't even need to be over charged. Just the normal high pressure of a .40 could be enough to rupture the case at the unsupported location.

UPDATE:
I retract my previous statement. Apparently I was wrong about the pressure differences. A quick search showed that the 9mm and .40S&W produce similar chamber pressures.

Now I have no idea what's going on. I do believe both issues mentioned in this thread to be the result of unsupported chambers. Why we haven't seen a 9mm fail in this manner is beyond me.

 

[Kilibreaux]

It's always a .40 S&W that goes "ka-boom."

 

[Irn-Bru]

This would give S&W a huge headache if they had to recall them over this. Not liking what I'm seeing either, my Shield was my EDC too. I'd like to hear what Smith say regrading this.

 

[Roger S&W]

This would give S&W a huge headache if they had to recall them over this. Not liking what I'm seeing either, my Shield was my EDC too. I'd like to hear what Smith say regrading this.

First, someone must show them Picture #1 from post #83 to them. They'll probably do what Glock did. Produce a new barrel with better chamber support. When will that be available? Probably at least a year from now.

 

[Roger S&W]

It's always a .40 S&W that goes "ka-boom."

Even though 9mm and .40S&W are both "high pressure" rounds, as Rastoff correctly stated above, we all know the .40S&W is just a more powerful round. More muzzle energy. More blast. Anybody who shoots the two calibers knows that.
BTW, I never heard of Glock 9mm KaBooms either.
Only .40S&W chambered pistols. (prior to their newer barrels with better chamber support)

 

[Roger S&W]

The close up photography above is excellent. I just checked chamber support on the M&P40c and Shield 40 side by side. There appeared to be a minute difference. The Shield having less support. Really hard to discern the difference for my eyes.
However, it's hard to argue with pitbulloncrack's excellent photography.

 

[Hound]

OK, I found it. Here is the thread that I was talking about: http://smith-wessonforum.com/smith-...eld-9-going-back-s-w-again.html#post137711304

Here are the pics that are making me think harder about this situation:

First, this is my 9mm barrel with a snap cap in it:

Here is Astocks2622's barrel:

If you look closely at the feed ramps, you'll see that Astocks2622's is much wider than mine and cut further into the chamber. Now, a 9mm has a lower chamber pressure than a .40S&W does. His brass was simply exhibiting bulges near the head. If it had been a .40S&W, he may have experienced a catastrophic failure too.

LieutenantFF,
Would you please look at your feed ramp and see if it's cut too wide or deep? If it is, this would lead to an unsupported case. With as much pressure as a .40S&W develops, I could see a failure like you had if a case was just a little weaker at the base; even with normal loads.

9mm Luger and 40 S&W both have SAAMI max pressures of 35,000 PSI.

 

[feelinlucky]

...simple case ruptures due to an unsupported chamber.

Wrong. Simple case ruptures due to excessive chamber pressure. If the chamber was "unsupported" the gun would kaboom the first time it was shot.

If you're afraid of the gun, instead of making unsubstantiated claims, sell it. You'll find plenty of ready and willing buyers here and elsewhere.