M855: what does it "penetrate"?


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ArmedBear
May 14, 2008, 12:08 PM
What do "penetrator" rounds actually go through?

Steel plate? How thick?
Body armor? What level?

Backstop concerns? Do they have hunting applications (assuming that ball rounds are legal for the game and location in question)?

Or none of the above?

Anyone know?

Thanks to anyone who does.

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taliv
May 14, 2008, 12:13 PM
you'll need to login, but this is where you want to go for that info: http://www.tacticalforums.com/cgi-bin/tacticalubb/ultimatebb.cgi?ubb=forum;f=78

DoubleTapDrew
May 14, 2008, 01:05 PM
According to the Ammo Oracle:
M193: Defined by: Mil-C-9963F
55 grain bullet (q 2 grains) at a muzzle velocity of 3,165 (q 40 fps) from a 20" barrel @ 78 feet from the muzzle. Accuracy: maximum of a two inch mean radius at 200 yards from ten 10 shot groups (~3 MOA). "Statistically average" M193 ranges from 1.2 to 1.6 inches mean radius, which is equivalent to 1.8 to 2.4 MOA. Velocity runs about 3,200 fps due to gas loss through the port. Accuracy is typically around 2 to 2+ MOA from an M16A1 rifle at ranges of 100 to 300 yards. M193 ammunition should have 1:12 twist or faster. M193 is barely stabilized with 1:14 at ambient temperatures and will not stabilize at all when the air temperature drops below freezing.

M855: Defined in MIL-C-63989
NATO specifications for M855 Ball require a 61.7 grain (q 1.5 grains) with a hardened steel penetrator at a velocity of 3,000 fps (q 40 fps) from a 20" barrel @ 78 feet from the muzzle. Typical velocity 15 feet from the M16A2's muzzle is 3,100 fps. Accuracy: maximum of approximately four MOA over the 100 to 600 yard range. Typical accuracy of average lots in an M16A2 is about 2+ MOA. This round must also penetrate a nominal 10 gauge SAE 1010 or 1020 steel test plate at a range of at least 570 meters (623 yards). The M193 round will penetrate this same plate reliably at 400 yards and about half the time at 500 yards. The 5.56mm and 7.62mm NATO rounds will penetrate it reliably out to 700 yards or more. Because the steel penetrator increases the length and changes the weight distribution of the SS-109 bullet, it is suitable for use only in barrels with a twist of one turn in nine inches or faster. 1:10 twist will barely stabilize this round and not below zero degrees F.

If 5.56 is legal to hunt with I suppose you could use it but I'd be concerned about using a fragmenting bullet in something you are going to eat (makes my gums hurt just thinking about it).

IndianaBoy
May 14, 2008, 01:19 PM
Very briefly:

Hunting: Very poor choice for hunting anything.

Penetration:

Steel plate: Depends on how thick. I know that you don't want to use them on mild steel targets. Not sure how hardened steel poppers would stand up. I would NOT use them on popper targets that I bought for myself, so I won't use them at my range for steel.

Body Armor: Like a hot knife through butter. Like most high power rifle rounds.


Backstop concerns: A typical rifle range berm will easily stop them.

Neo-Luddite
May 14, 2008, 03:54 PM
AP it's not--legally or in practical terms. My best undestanding is that it improves nominal penetration at long range--say past 200 meters or so. It can supposedly punch through softer body armor out that far as a result of the penetrator.

For hunting, I suppose, if you're talking coyote or prarie dog--sure.

ArmedBear
May 14, 2008, 07:23 PM
For hunting, I suppose, if you're talking coyote or prarie dog--sure.

Yeah. I should have specified that...

In most of the West, soft-nose bullets are required for big game anyway, so that's what I meant.


Backstop concerns: A typical rifle range berm will easily stop them.

I often shoot at an indoor 100-yard range. I know that's a rarity, and it seems even stranger in our mild climate. Guess I should have specified that, too.:)

IndianaBoy
May 14, 2008, 07:53 PM
FMJ or steel core bullets from a 223/5.56 are a poor choice for hunting anything.

In a coyote they are likely to create a very neat hole with minimal tissue destruction. This is even more true in a prarie dog. Sure the animal will probably die eventually, but this is a cruel way to kill an animal.

If you are going hunting, the extra cost for a few expanding or fragmenting varmint rounds is negligible compared to making a humane kill.

Bitmap
May 14, 2008, 08:17 PM
I know from experience that it will go through a telephone pole at 200 yards. I don't know if M193 will do that or if .223 JSP rounds will do that.

JNewell
May 14, 2008, 08:59 PM
I have seen it go through single-plate brake rotors at 25 yards. IIRC, the thickness was in the range of 3/8-7/16" or so.

hank327
May 14, 2008, 08:59 PM
IIRC, it was mainly intended to penetrate a steel GI helmet at 600 meters. The 55 grn M193 round used in the M16A1 wouldn't do that reliably at that range.

ny32182
May 14, 2008, 09:13 PM
Yeah, I've always heard that the ability to penetrate both sides of a standard helmet at ~600 meters was one of the requirements, something that the M193 and standard 7.62 rounds could not do.

benEzra
May 14, 2008, 09:44 PM
One thing that a lot of people don't realize is that M855 penetrates somewhat less in hard objects at closer ranges than M193 does, due to M855's lower velocity. M855's better ballistic coefficient and greater mass give it more penetration at longer ranges, though, where the M193 was considered deficient.

HorseSoldier
May 14, 2008, 09:59 PM
At close range it will easily make it through any part of a car door. It has pretty good odds of making it out the far side of an automobile as well, depending (so far as I can tell) on how much yaw the bullet goes into, and what it contacts in the first door and interior of the vehicle.

Soybomb
May 14, 2008, 10:02 PM
Neat post, I've always wondered what the practical penetrative properties are!

alsaqr
May 14, 2008, 10:51 PM
'Do they have hunting applications (assuming that ball rounds are legal for the game and location in question)?"



i often hunt wild hogs with 5.56mm M193 ball. When hit right the hog often dies as if struck by a bolt of lightning. If the bullet does not hit bone, it penetrates for about 6", yaws and breaks up. Unless it is a really big hog the bullet will exit a with a shoulder shot.

Shot these two immature boars with M193 rounds last week. Red one was hit behind the shoulder. He ran 50-60 yards and died. The black one was running full tilt, quartering slightly away when the bullet hit him to the rear of the shoulder: It shredded the liver and lungs and he fell over kicking on the ground. Did a finishing shot in the head.

http://www.thehighroad.org/showthread.php?t=361283

MechAg94
May 14, 2008, 10:51 PM
FMJ or steel core bullets from a 223/5.56 are a poor choice for hunting anything.

In a coyote they are likely to create a very neat hole with minimal tissue destruction. This is even more true in a prarie dog. Sure the animal will probably die eventually, but this is a cruel way to kill an animal.

If you are going hunting, the extra cost for a few expanding or fragmenting varmint rounds is negligible compared to making a humane kill.

Is this comment from experience? I am trying to figure out why a soft point round would be more effective in a coyote or a poodle than M193. Is it supposed to fragment reliably? I can understand some of the varmint rounds, but a coyote is a bit bigger than the average varmint.

Soybomb
May 15, 2008, 12:06 AM
Is this comment from experience? I am trying to figure out why a soft point round would be more effective in a coyote or a poodle than M193. Is it supposed to fragment reliably? I can understand some of the varmint rounds, but a coyote is a bit bigger than the average varmint.
Correct, the jsp should fragment sooner and more reliably. Part of the reason why mk262 is considered a better round than m193 is its earlier yaw.

From DocGKR http://www.tacticalforums.com/cgi-bin/tacticalubb/ultimatebb.cgi?ubb=get_topic;f=78;t=000059#000004
The U.S. M855/Belgian SS109 62 gr FMJ boat-tail bullet has a partial steel core surrounded by a copper jacket and a muzzle velocity of around 3034 f/s. The behavior of this bullet is very similar to that of the 5.56 x 45mm M193 bullet. The wounds created by the M193 and the M855/SS109 are nearly identical. Typically, the bullet enters the tissue, leaving a small punctate entrance wound, and then travels point forward for approximately 4.7". If the bullet leaves tissue at this point, it will leave a small punctate exit wound and will have caused minimal tissue disruption along the wound tract. If it continues to travel in tissue, it will yaw to 90 degrees at this point, flatten, and fracture at the cannelure. The flattened bullet nose remains in one piece and retains about 60% of the original bullet weight. The other 40% of the bullet behind the cannelure shatters into many fragments that can spread up to 2.75" radially away from the wound tract. These fragment each cut their own path through the surrounding tissue, multiply perforating it. Temporary cavitation then exerts its stretch effects on this weakened tissue, synergistically increasing the permanent cavity by detaching tissue pieces. Wounds in body segments thicker than 4.7" show greatly enlarged permanent and temporary cavities and can create stellate exit wounds of 3.5 to 4.7" measured form the ends opposite the skin splits. The degree of bullet fragmentation is dependent on velocity. As the range to the target increases, the striking velocity decreases, limiting bullet fragmentation. At ranges above 200 m or so, the bullet remains intact and simply yaws.

When 5.56 x 45 mm bullets fail to yaw, fragment, or deform within tissue, the results are relatively insignificant wounds, similar to those produced by .22 long rifle bullets. This is true for ALL 5.56 mm bullets, including both M855 and M193.


In 1980, I treated a soldier shot accidentally with an M16 M193 bullet from a distance of about ten feet. The bullet entered his left thigh and traveled obliquely upward. It exited after passing through about 11 inches of muscle. The man walked in to my clinic with no limp whatsoever: the entrance and exit holes were about 4 mm across, and punctate. X-ray films showed intact bones, no bullet fragments, and no evidence of significant tissue disruption caused by the bullet’s temporary cavity. The bullet path passed well lateral to the femoral vessels. He was back on duty in a few days. Devastating? Hardly. The wound profile of the M193 bullet (page 29 of the Emergency War Surgery—NATO Handbook, GPO, Washington, D.C., 1988) shows that most often the bullet travels about five inches through flesh before beginning significant yaw. But about 15% of the time, it travels much farther than that before yawing—in which case it causes even milder wounds, if it missed bones, guts, lung, and major blood vessels. In my experience and research, at least as many M16 users in Vietnam concluded that it produced unacceptably minimal, rather than “massive”, wounds. After viewing the wound profile, recall that the Vietnamese were small people, and generally very slim. Many M16 bullets passed through their torsos traveling mostly point forward, and caused minimal damage. Most shots piercing an extremity, even in the heavier-built Americans, unless they hit bone, caused no more damage than a 22 caliber rimfire bullet.”

Fackler, ML: “Literature Review”. Wound Ballistics Review; 5(2):40, Fall 2001

jackdanson
May 15, 2008, 02:57 AM
At close range it will easily make it through any part of a car door. It has pretty good odds of making it out the far side of an automobile as well, depending (so far as I can tell) on how much yaw the bullet goes into, and what it contacts in the first door and interior of the vehicle.

It will probably slice right through a car. An aquiantance from my high school got killed about 2 years ago when a carjacker ahole shot him through the back of his car. He drove off when the guy tried to take it and for some reason the scum decided to shoot at the back of the car. 9mm went into the trunk, through the backseat, through the front seat and into the guy. He was a nice guy, 1st gen Bosnian who joined the army (marines? can't remember) senior year.

No doubt a .223 would go through anything except an axle, wheel, or engine block.

JNewell
May 15, 2008, 09:17 PM
No doubt a .223 would go through anything except an axle, wheel, or engine block.

Based on what I've seen personally, it might just go through a wheel, including the rotor.

This wouldn't make 5.56x45 my first choice for vehicle stops, though...

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