MP5 Style Weapon for Home Defense?

[MitchellCT]

If you want a 9mm carbine, go with the beretta.

It won't bankrupt you.

[DefensiveCarry.com]

[10thmtn]

Just want to clear up one thing from earlier in this thread...

With a longer barrel from a sub-gun, a 9mm JHP may actually penetrate LESS, not more, due to the increase in velocity over a pistol length barrel. The increased velocity can cause the JHP to open up so quickly and violently, that the bullet fragments, resulting in shallow penetration.

If you are going to go with a 9mm carbine, choose your load wisely.

Personally, I only see a need for two home defense weapons - a handgun (for moving inside the home), and a shotgun (for covering the barricaded door to your safe room until the cavalry shows up to clear the house). A handgun leaves a hand free, for things like light switches, door knobs, the phone, and grabbing the kids. And I trust a shotgun at close quarters much more than any carbine or sub gun - with #1 buckshot, every trigger pull is delivering 16 pellets into the target virtually simultaneously.

If I lived in a more suppressor-friendly area, I might feel differently. Hmmm...maybe I should keep a few sets of earpro in my bedroom.

[HotGuns]

Not a problem. You just keep shooting until the threat stops.

That might be one shot...or 30.

[buckeye .45]

You mean like this?

The MP5SD3

Attachment 54403
Its fast,accurate, easy to manuever and the only sound that wakes up your wife will be the sound of the perps body crashing to the floor.

Plus, it looks cool sitting on the kitchen table. Whats not to like?

Well, honestly, I don't really like your kitchen floor, but that might just be me.

Thats certainly a nice thing to have around though.

[Nix]

I like the idea of the MP5, Uzi, or short AR because a shooter is inherently more accurate when using a two handed weapon with a longer sighting length. But for CQC, it is hard to beat a shotgun with a buckshot. Additionally, I'd be a bit worried that the rounds from an AR might end up over at the neighbor's house in one of their kids. No worries with a 12ga.

[10thmtn]

Not a problem. You just keep shooting until the threat stops.

That might be one shot...or 30.

Again, this is true.

But, there is nothing wrong with doing your due diligence and selecting the best round for your application. Bottom line is that you cannot just assume that what works well in your pistol is going to work better (or even as well) when fired out of a sub-gun.

[10thmtn]

I like the idea of the MP5, Uzi, or short AR because a shooter is inherently more accurate when using a two handed weapon with a longer sighting length. But for CQC, it is hard to beat a shotgun with a buckshot. Additionally, I'd be a bit worried that the rounds from an AR might end up over at the neighbor's house in one of their kids. No worries with a 12ga.

Not true.

The light/fast 5.56 loadings tend to fragment when going through walls. Buckshot and pistol rounds actually tend to penetrate more, since the buckshot pellets and pistol bullets tend to weigh more than the lighter 5.56 bullets.

Now, if you are using bird shot, then you are correct. However, bird shot does not penetrate enough to reach the vitals on a human, and is not recommended for self defense.

I use #1 buckshot. Given that I would only be using it to cover the door to our bedroom, I do not plan on missing. The other thing to consider is that BGs know that interior walls will not stop bullets. There is a possibility of needing to return fire through your own walls. In such a case, I want better penetration than what 5.56 offers, which is one other reason I use a shotgun.

[Nix]

Not true.

The light/fast 5.56 loadings tend to fragment when going through walls.

Well, you may know better than I; but in my experience shot loses energy quickly and doesn't travel very far. While it's true that 5.56 rounds can fragment, as can any round, I've also seen 5.56 take apart a cinder-block wall and go cleanly through plaster and wood. I'm not a huge fan of the 5.56, but I do respect the energy it packs. I certainly wouldn't count on the idea that rounds from an AR might fragment as a safety plan in planning for home defense.

[10thmtn]

You are correct about the safety rule - "know your target, and what is beyond it."
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That said, this is what I was getting at:

(Source: Best Choices for Self Defense Ammo)

WoundProfilesAfterWallBarrier.jpg

Note, however, that this is showing wound patterns in gel, after first going through a wall.
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Now - in regards to a complete miss, you may be correct. Here is some testing:

The Box O' Truth #3 - The Shotgun Meets the Box O' Truth - Page 2

From their "Lessons Learned:"

Lessons learned:
1. Notice that the #4 and #1 Buck penetrated 6 boards. In previous tests, 9mm, .45 ACP, and M-193 out of an AR all penetrated all 12 boards.

So, it seems that these [shotgun] loads do not "over-penetrate" as much as some have led us to believe.

The 00 Buck penetrated 8 boards, but was stopped by the 9th. Still not as much penetration as the pistol or rifle loads.

The slug penetrated all 12 boards.
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Frankly, I was surprised that the shotgun did not penetrate more than it did. I had been led to believe that they penetrated more than a .223 rifle or a 9mm or .45 ACP. Such was not the case.

Amazing what you can learn by doing a little testing.
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But doesn't 00 Buck penetrate too much in interior walls to be a "safe" load in a home?
Yes, it does penetrate a lot. But any load that is going to be effective will need to penetrate walls to have enough power to penetrate bad guys. If our only concern was to be sure we didn't penetrate walls, we would use BB guns. However, BB guns will not stop bad guys.

Therefore, we must use loads that will STOP bad guys, and this means that they will also penetrate walls. So, be sure you hit the bad guy and do not shoot into walls where loved ones are on the other side.

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So, if you are concerned about neighbors in the event of a miss, it does indeed seem like buckshot is better than rifle or pistol rounds. If you are worried about shooting through walls inside your own home, then you'd best plan on not missing.

[Nix]

If you are worried about shooting through walls inside your own home, then you'd best plan on not missing.

Sage enough.

BTW, I am loading #4 Buck in my 12ga., but you have me thinking about #1. I read a Navy study (Old, long ago) that suggested #4 was a good defensive round. I also read about it being used in Vietnam. Subsequently some DoD forces made a "Panama" load that was a mixture of different sized shot. But your data makes #1 or 00 look fairly attractive.

[10thmtn]

This is the data that led me to #1 buckshot. However, it can be hard to find - I had to order it on-line.

Nothing wrong with OO buckshot, either. And really, I would be OK with #4 buck as well. It's just that #1 buck seems the happy middle between pellet count vs penetration depth.

Sorry for the thread highjack...back to 9mm carbines and sub-guns (though we know shotguns are better).

[redbeardsong]

I know a lot of agencies are trading in their MP5s for AR's because of over-penetration issues with the 9mm. Presumably they're using FMJ, because with how fast they blow through a mag, JHP's would get quite expensive.

[Rockymonster]

This is the data that led me to #1 buckshot. However, it can be hard to find - I had to order it on-line.

Nothing wrong with OO buckshot, either. And really, I would be OK with #4 buck as well. It's just that #1 buck seems the happy middle between pellet count vs penetration depth.

Sorry for the thread highjack...back to 9mm carbines and sub-guns (though we know shotguns are better).

No worries on the thread highjack, this has been a valuable exchange of information and opinion....thank you!

[jonconsiglio]

I know a lot of agencies are trading in their MP5s for AR's because of over-penetration issues with the 9mm. Presumably they're using FMJ, because with how fast they blow through a mag, JHP's would get quite expensive.

They don't blow through rounds. When running any full auto, there's a discipline needed and even more so with law enforcement. Some of the older MP5's had feeding issues with HPs but one fed them just fine.

[COlongshot]

I agree with the sbr suggestions, just surprised this one hasn't popped up

tech_01.PNG

KRISS Vector CRB/SO