intriguing newbie question


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General Geoff
September 3, 2008, 01:16 PM
A guy I know who's not too knowledgeable about firearms but knows enough to be dangerous (so to speak ;)) thinks that a .577 Nitro Express and a 4-Bore round could penetrate a level IV trauma plate. I don't think they would, as they have a relatively low muzzle velocity (albeit very high mass). What do you guys think? Not that it'll likely ever happen, but it's an intriguing question nonetheless.

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elChupacabra!
September 3, 2008, 01:23 PM
Man... I don't know... I wonder if it would have to make it through the plate to still kill you? I'm thinking the shock of the impact - even if it stayed outside your body - could probably break your sternum / ribs / etc and might give you a heart attack... I dunno? Imagining it, I bet it would be like being hit in the chest with a baseball bat....

General Geoff
September 3, 2008, 01:28 PM
With soft armour I'd agree with you, but a trauma plate is rigid, and if the round didn't penetrate, practically all the force of the round would be expended in cracking/shattering the plate. So you'd be fine after one shot. Following shots, though... ;)

Z-Michigan
September 3, 2008, 01:30 PM
It's probably academic since anyone wearing level IV armor in an area where those cartridges are common (think hunters in central Africa) will probably die of heat exhaustion and fatigue before they can get shot.

However, the specs required for level IV are extremely tough, and I would expect it to stop either of those rounds. Also, since level IV is usually (always?) a hard plate, it should spread out the impact well and prevent severe blunt trauma injuries. The guy getting shot would probably be knocked over (as would the guy shooting the rifle, look up .577 Tyrannosaur for an amusing video) but likely be OK.

Norinco982lover
September 3, 2008, 01:30 PM
I agree with Geoff. If the first shot doesn't kill/disable you by knocking you over (you could hit your head or another part of your body with the fall) then the second shot will probably crack something into pieces.

Tarvis
September 3, 2008, 01:38 PM
Does anyone have some level IV armor and a rifle in .577 nitro we can test? :evil:

Most likely, you would suffer serious injuries from the energy transfer. The plate will take the brunt of it, but it would certainly knock you off your feet. The only way that much energy wouldn't kill you is if it was spread over a large enough area of your body. I don't know how big these plates are, but an 8"x10" plate would probably shatter your sternum.

gvnwst
September 3, 2008, 01:46 PM
if you used a 950jdj (a new 4-bore) you will be ded. thats a 1/2 lb bullet giong 2200fps!!! i think even if the plate stopped the bullet, you would be thrown back a couple of dozen feet. :evil:

General Geoff
September 3, 2008, 02:11 PM
After looking up 950JDJ, I have to agree that it would probably shatter the trauma plate and proceed to embed most of the plate into the poor guy's internal organs. That thing is essentially a miniature artillery piece.

Z-Michigan
September 3, 2008, 03:18 PM
I had to look up the 950JDJ. It's ridiculous. OK, it would probably go through the Level IV, and even if it didn't it might knock the wearer far enough to kill him.

I'm a little puzzled at how it got a sporting use exception from being a destructive device, as I'm all for cool toys and yet I can't think of any sporting use for it.

And now we return to reality...

Acera
September 3, 2008, 04:13 PM
Come on guys,

Most likely, you would suffer serious injuries from the energy transfer. The plate will take the brunt of it, but it would certainly knock you off your feet. The only way that much energy wouldn't kill you is if it was spread over a large enough area of your body.


and even if it didn't it might knock the wearer far enough to kill him.


Have we forgotten that the rifle is fired from the shoulder?? A trauma plate has a far bigger footprint than the but cap on the rifle. I remember some old dude saying for every action there is an equal and opposite reaction. So the energy transferred back is the same as that going out the other end.

That flying backward through plate glass windows is Hollywood crap.

GigaBuist
September 3, 2008, 04:32 PM
Have we forgotten that the rifle is fired from the shoulder?? A trauma plate has a far bigger footprint than the but cap on the rifle.

I'm checking the Wikipedia page on the cartridge and it says the rifles usually weigh between 80 and 110 lbs. Muzzle energy is 38,000 ft. lbs.

I'd dare say that might actually knock somebody on their fourth point of contact.

Sunray
September 3, 2008, 05:04 PM
"....577 Nitro Express..." Which one? There are several. From how far away? A 3" fires a 750 grain bullet at around 1900fps with 7,000 ft-lbs of muzzle energy. Trauma plate or not it's gonna hurt.
A 4 bore, roughly 26.7mm, fires a 2,000 grain bullet with 7400 ft-lbs of muzzle energy. That'd hurt too. Maybe more.
Both of 'em will blow you out from under your hat.

DoubleTapDrew
September 3, 2008, 05:05 PM
the rifles usually weigh between 80 and 110 lbs. Muzzle energy is 38,000 ft. lbs.

That's what I don't understand about people saying a rifle that would knock somebody over would knock the shooter over equally. It doesn't feel like my shoulder is getting hit with 4000ft/lbs of energy when I touch off a .300 Weatherby, let alone .50bmg shooters.

doc2rn
September 3, 2008, 05:16 PM
I think the impact of the bullet on the plate would either cause a tension pneumothorax or a conductivity problem resulting in miocardial infarction.
I dont think even dragon scale armour can protect you from that slug.

Girodin
September 3, 2008, 05:18 PM
Have we forgotten that the rifle is fired from the shoulder?? A trauma plate has a far bigger footprint than the but cap on the rifle. I remember some old dude saying for every action there is an equal and opposite reaction. So the energy transferred back is the same as that going out the other end.

Hold that rifle 6" off of your shoulder pull the trigger and see what it does to you. Although the forces may be the same they way they are applied to the shooter and the reciepient are not. Having the rifle tightly tucked into your shoulder with a firm grip is not the same as the projectile hitting from a distance. If you dont have a 577 nitro you could do this with a lowly 12 gauge and it would illustrate the point.

Z-Michigan
September 3, 2008, 06:07 PM
Have we forgotten that the rifle is fired from the shoulder?? A trauma plate has a far bigger footprint than the but cap on the rifle. I remember some old dude saying for every action there is an equal and opposite reaction. So the energy transferred back is the same as that going out the other end.

That flying backward through plate glass windows is Hollywood crap.

For any normal or sane rifle I agree with you, but the 950 JDJ is well outside the normal and sane categories. I think 38,000 ft-lbs will actually knock someone over. The rifle shooting it isn't meant to fired from the shoulder.

Still enjoying this little excursion from reality, FWIW.

Acera
September 3, 2008, 06:08 PM
GigaBuist wrote:
I'm checking the Wikipedia page on the cartridge and it says the rifles usually weigh between 80 and 110 lbs

Well that is what you get for reading Wikipedia. Holland and Holland says theirs weigh 10 lbs, did you really believe a shoulder fired rifle would weigh 100 lbs??

Getting knocked on you butt is more of a reaction to an unexpected force than from the brute energy of the projectile. You are anticipating the recoil of the weapon when you lean into it, and know you are discharging it. Watch videos of people wearing vests who know they are about to get shot, they don't go flying backwards. (remember that guy from second chance body armor and his .44?)

Girodin wrote:
Hold that rifle 6" off of your shoulder pull the trigger and see what it does to you.

The physics are the same, it does not gain energy the if it is not on you shoulder.

The trauma plates I am familiar with are about the same weight as the rifle (the weight and the area of the recoil pad being what makes the rifle shootable.) The significant increase is surface area of the plate would lessen any trauma associated. Far greater focused energy from firing the rifle, than the energy transferred through the entire area of a trauma plate.

Acera
September 3, 2008, 06:41 PM
Ok upon further reading, it looks like the subject of this post changed from a .577 Nitro Express. That is what I am talking about.

Some others have started a conversation on a 950JDJ, not the OPs question.

Claymore1500
September 3, 2008, 07:26 PM
I'm thinking it would put a hole in you and pull the plate in after it .

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