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Old 08-04-2009, 05:35 PM   #31
Fred Brackin
 
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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Originally Posted by Ragitsu View Post
It's one thing to be positive, but another to be dishonest.
It's the manufacturers that are being dishonest sometimes. ISTR that FN has claimed that the P90 round was designed to tumble when the opposite is pretty much the truth. It's more point-heavy than anything else I can think of.

The show just isn't playing "Military Mythbusters" all the time. They do sometimes let Mac really test the gear. That 2000 yard + cold bore shot with the sniper rifle was pretty impressive. Mostly though they have to take the manufacturer claims as truth. They have to have the access and the free demos or there's no show.
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Old 08-04-2009, 05:46 PM   #32
DouglasCole
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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Originally Posted by Fred Brackin View Post
ISTR that FN has claimed that the P90 round was designed to tumble when the opposite is pretty much the truth. It's more point-heavy than anything else I can think of.
http://www.d3lf.net/p90/ammo.htm

There's a nice cross-section of the SS190 on that site.
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Old 08-04-2009, 05:59 PM   #33
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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Originally Posted by Fred Brackin View Post
It's the manufacturers that are being dishonest sometimes. ISTR that FN has claimed that the P90 round was designed to tumble when the opposite is pretty much the truth. It's more point-heavy than anything else I can think of.

The show just isn't playing "Military Mythbusters" all the time. They do sometimes let Mac really test the gear. That 2000 yard + cold bore shot with the sniper rifle was pretty impressive. Mostly though they have to take the manufacturer claims as truth. They have to have the access and the free demos or there's no show.
I suppose if you're in the biz, you know what's what, while for the public it could be a little propagand-ish.

The 30mm Bushmaster disappointed me, since they only fired single rounds ;)
It would have been nicer to see a smoking crater where that block wall-hut
was :)

>
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Old 08-04-2009, 06:08 PM   #34
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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Originally Posted by Shrale View Post
The 30mm Bushmaster disappointed me, since they only fired single rounds ;)
It would have been nicer to see a smoking crater where that block wall-hut
was :)
Reminds me of the Mythbusters where they cut down a tree with an M134.
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Old 08-04-2009, 06:47 PM   #35
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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http://www.d3lf.net/p90/ammo.htm

There's a nice cross-section of the SS190 on that site.
<cut and paste>
As the bulk of the bullet mass is located in the front of the bullet, once it strikes it tends to tumble, in the process giving up most of its momentum and striking power immediately. This produces a large wound cavity and high-energy transfer;
</cut and paste>

Yep, there it is. BS in black and white.

If anyone wonders it really is having the center of mass in the rear of the bullet that causes bullets to tumble after they lose gyroscopic stabilization.

That gelatin block shows a typical temporary cavity (which closes rapidly) with the bullet still in the target. By FBI standard's that's inadequate penetration and not a desirable feature.

The FBI wants a minimum of 12 inches penetration and that block probalby showed only about 9. It'a point in favor of the HKP7's round that it penetrates 11 inches in gelatin. That's almost good enough. The wound track is still small of course.
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Old 08-04-2009, 06:53 PM   #36
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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Originally Posted by Fred Brackin View Post
<cut and paste>
As the bulk of the bullet mass is located in the front of the bullet, once it strikes it tends to tumble, in the process giving up most of its momentum and striking power immediately. This produces a large wound cavity and high-energy transfer;
</cut and paste>

Yep, there it is. BS in black and white.
You know, I think I glossed over this because I have read the CORRECT statement so many times my brain said "I know what's coming here."

Now, I would accept (or at least consider) that the aluminum portion and the steel portion, held together only by the jacket, naturally fragment on impact, helping wounding or whatever. But the statement quoted above is just daft.
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Old 08-04-2009, 07:07 PM   #37
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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The show just isn't playing "Military Mythbusters" all the time. They do sometimes let Mac really test the gear...
I would really like to see Mac script himself on Futureweapons. Sure, he used to be a SEAL, but Mac is an actor now, and actors say what they are told to say, or they get fired. I choose to believe that is the reason why the show can be so inane.

I want to hear his thoughts on the subject matter. Ask the questions he wants to ask. In particular, compare the new stuff to what is out there now.
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Old 08-05-2009, 01:16 AM   #38
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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Originally Posted by Fred Brackin View Post
They do sometimes let Mac really test the gear. That 2000 yard + cold bore shot with the sniper rifle was pretty impressive.
That was pretty awesome, yeah. Cold-bore shot with an unfamiliar weapon/ammunition combination, and he got a better shot than the other guy who was familiar with the weapon (And got several shots with it, if I'm remembering right).
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Old 08-05-2009, 02:44 AM   #39
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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Originally Posted by Fred Brackin View Post
Yep, there it is. BS in black and white.
Well, the statement is sort of true, in the sense that just about any bullet will tumble on hitting flesh, probably including this one. However, the implication that being tip-heavy makes tumbling more likely is laughable.
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Old 08-05-2009, 06:59 AM   #40
DouglasCole
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Default Re: H&K MP7A1 versus Ballistic Helmet [High-Tech]

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Well, the statement is sort of true, in the sense that just about any bullet will tumble on hitting flesh, probably including this one. However, the implication that being tip-heavy makes tumbling more likely is laughable.
Any ogive bullet will want to go from metastable to stable by yawing and thus tumbling in a denser medium than air. Pistol bullets don't tumble much, being mostly slightly rounded cylinders with a fairly even mass distribution. Still, the aspect ratio of most rifle bullets is about 4; the highest aspect ratio pistol bullet that I've run across is the 9mm at about 2. Longer bullets (and I belive the 5.45x39mm is around a 5) will tumble and yaw more; they'll also be more likely to fragment, since they're structurally weaker.
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