My understanding is that the M855 was designed to penetrate a steel helmet at an extended range. However, penetration, especially of hard materials, relies heavily on velocity. So does the M855 actually do a better job of punching a hole in a steel helmet than the faster M193? From what I've seen the M855 doesn't really penetrate anything better than other .223/5.56 bullets, but is this where it really shines?
Does the M855 Penetrate Steel Helmets Better Than M193?
- Thread starter HGM22
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M855 was designed to penetrate Soviet Era commie body armor. M193 was deigned to tumble upon flesh entry making ragged and ugly internal wound channels. The services went heavy with M855 and then complained that it wasn't downing un-armored insurgent types because the penetrater zipped straight through soft tissue and need more hits to do the job. The fact that there is a steel core should make it a better use against a steel helmet. A Kevlar/synthetic helmet may be a different story.
entropy
Member
Sounds like a good question for Chopinbloc...........
mljdeckard
Member
Velocity is only one side of the equation. There is also increased mass, which is part of energy. It also has a steel penetrator core, which greatly increases penetration.
lysanderxiii
Member
According to NSMATCC testing, the SS109 can penetrate a steel M1 Helmet at ranges up to 1,300 meters.
At that range the speed of M193 has dropped considerably, and the construction of the bullet plays a much larger role in penetration. Penetration of hard materials depends on three things, velocity, mass and projectile construction. M193 has better velocity at short ranges, but as the range increases, the M855 begins to out perform the lighter, softer bullet.
The maximum range a 7.62mm M80 ball bullet will penetrate an M1 helmet is only 800 meters, and M193 is in the neighborhood of 600.
At that range the speed of M193 has dropped considerably, and the construction of the bullet plays a much larger role in penetration. Penetration of hard materials depends on three things, velocity, mass and projectile construction. M193 has better velocity at short ranges, but as the range increases, the M855 begins to out perform the lighter, softer bullet.
The maximum range a 7.62mm M80 ball bullet will penetrate an M1 helmet is only 800 meters, and M193 is in the neighborhood of 600.
FL-NC
Member
Ever really looked at a "steel" military issue helmet (which no one uses any more and you probably need to go to an antique shop or militaria show to buy)? Either 223 round will go through both sides at 300 meters. So I'm going to say it doesn't matter.
Shawn Dodson
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M193 was NOT designed to tumble - all pointed and many semi-pointed bullets yaw in soft tissue because the bullet's center of gravity is located toward the base. The spin stabilization used to stabilize bullet flight in air is insufficient to keep the bullet penetrating point forward when it penetrates flesh. Soft tissues are 700 times more dense than air. When the bullet penetrates soft tissues it seeks to achieve a state of stability. It does this by yawing 180-degrees to travel base forward. The bullet does not tumble end over end. Both M193 and M855 yaw. If penetration velocity is high enough they both will fracture at the cannelure as they yaw through 90 degrees. The cannelure is a weak point in the jacket and the stress placed on the bullet as it penetrates sideways, depending on velocity, will flatten the bullet causing to to extrude lead out the open base, and fracture at the cannelure and fragment. The fragments pepper surrounding tissues with small holes that are then torn open by the subsequent temporary cavity.
The issues with mild wounding effects caused by M855 are due to the fact that it is yaw sensitive. Some rifles do not stabilize the bullet as well as others and this causes the bullet to wobble in flight. This effect is called fleet yaw. In addition, because M855 is a compound bullet, with a steel tip and lead slug in its core, there are manufacturing variations that cause individual bullets and lots of bullets to be less stable than others, and this also causes the bullets to wobble in flight. Fleet yaw and bullet variation affect the bullet's angle of attack. A bullet that penetrates point forward will penetrate deeper before it yaws whereas a bullet that hits at a slight angle because it's wobbling will yaw at a shallower depth. Finally M855 was designed to be fired from the 20" barrel of the M249 SAW and M16A1. The shorter 14.5" barrel of the M4 carbine decreased velocity substantially which substantially decreased its wounding effects.
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Swampman
Old Fart
The original 4172 NATO spec from the early 80's stipulated that the new SS-109 (US designation M855) should be able to penetrate a US M1 (WWII style) steel helmet at 800 meters, the same penetration as 7.62x51 M80 ball.
I believe NATO changed the 4172 standard in 1993, but I don't know exactly what the changes were.
The new US M855A1 round is said to have considerably better penetration than the old M855 as well as better performance in soft tissue.
I believe NATO changed the 4172 standard in 1993, but I don't know exactly what the changes were.
The new US M855A1 round is said to have considerably better penetration than the old M855 as well as better performance in soft tissue.
Joshboyfutre
Member
I figure m193 is more effective within 200m but m855 is better 200m out to max.
Swampman
Old Fart
I agree with your post except for two points.
"...all pointed and many semi-pointed bullets yaw in soft tissue because the bullet's center of gravity is located toward the base."
Not all pointed bullets yaw, soft point bullets smash the point back so that the bullet is heavier at the front than the rear. This tends to keep them stable and traveling "point" forward.
Frangible bullets like the Barnes Varmint Grenade don't tumble either, they pretty much just explode on contact.
"Finally M855 was designed to be fired from the 20" barrel of the M249 SAW and M16A1."
I'm pretty sure it was designed for the M16A2 (either that or the M16A2 was designed for the M855).
The 1/12" twist of the old 'A1 barrel won't stabilize M855.
benEzra
Moderator Emeritus
M855 holds on to its velocity better at range (more mass and better BC), so *at 800 meters*, it has much more penetration ability than M193. M193 generally out-penetrates M855 in steel at much closer ranges, though, due to its higher initial velocity.
Berger.Fan222
Member
http://www.dtic.mil/dtic/tr/fulltext/u2/a567525.pdf
If you look at Table 1 of the linked paper, you will see that m855 penetrates both 1/4" steel plate and composite armor at lower velocities than m193. The m855 also penetrates at lower velocities than solid copper bullets and solid brass bullets.
If you look at Table 1 of the linked paper, you will see that m855 penetrates both 1/4" steel plate and composite armor at lower velocities than m193. The m855 also penetrates at lower velocities than solid copper bullets and solid brass bullets.
entropy
Member
855 keyholes out of A1's, at @ 200 meters. 193 gives poor accuracy out past 300 meters no matter what you shoot it out of. As for helmet penetration......IDK. Still think it's a good question for chopinbloc.
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lysanderxiii
Member
The current requirement for 5.56mm NATO Ball is the bullet (except tracer) shall completely perforate a 3.5mm thick, SAE 1010 or SAE 1020 plate hardened to B55 - B70 at 570 meters at zero obliquity.
The current requirement for 7.62mm is the same except that the plate thickness is set at 3.42mm and the range is only 550m.
EDIT: 7.62mm AP must penetrate the standard plate at 1100m.
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C-grunt
Member
855 keyholes out of A1's, at @ 200 meters. 193 gives poor accuracy out past 300 meters no matter what you shoot it out of. As for helmet penetration......IDK. Still think it's a good question for chopinbloc.
Ive had acceptable accuracy with M193 out to 550 yards.
Penetration relies on mass, velocity, projectile construction, projectile configuration and angle of incidence among other factors.
Penetrating one-eighth inch of carbon steel with a projectile is not much of a challenge. Obtaining "zero obliquity" (in other words, meaning the projectile is perfectly square to the surface at impact) on a shape composed of complex curves like a helmet is another matter entirely. Whether steel or modern polymer, the helmet is designed less to resist penetration than it is to deflect projectiles.
At any distance where a head-shot is practical, any of the .223 military ball cartridge will, assuming the proper angle of incidence, penetrate the helmet. And if it penetrates the helmet, it will almost certainly have sufficient residual energy to penetrate the skin, muscle and bone on the other side and cause massive distruption to the white and gray material whose consistency is that of room-temperature butter.
While some bullets are quite capable of penetrating a helmet, what we have seen in battle is that once thru, they tend to deflect, bounce off the skull, then ricochet off the interior to hit the skull again, sometimes burying under the skin.
It's been remarked that the survivors have an opinion a straight thru and thru would be preferable to the permanent results of a bullet trapped inside the helmet with the human head to play with.
Moot point for the most part as the helmet is actually to protect the soldier from overhead airburst of artillery shells - hence the improvisation during WWI to include it in the combat uniform. Considering how a helmet of any description covers the top of the skull, the much smaller portion exposed to frontal fire is tiny compared to the amount exposed underneath - the human face.
No helmet we currently use covers that critical area. That was a consideration in the era of edged weapons but once gunpowder came into play note carefully that helmets actually came into disuse except for ceremonial purposes. It was the timed fuze and air burst applications which brought it back. The invention of the proximity fuze made it even more imperative as first rounds on target didn't need to be adjusted, they were on the mark.
Bullet penetration by other armed marksmen is actually the usual myopic thinking posed by any armed service - "how will our tanks do against other tanks?" thinking, when the actual application is "how will our tanks do ranging behind their lines wreaking havoc in their supply lines or command encampments?" The ability of helmets to resist ballistic penetration by some other soldiers bullet is symmetric warfare, note carefully those skilled warriors who practice asymmetric warfare do NOT wear helmets.
More often than not, they wear battle beards, which are as much protection as any helmet. : )
It's been remarked that the survivors have an opinion a straight thru and thru would be preferable to the permanent results of a bullet trapped inside the helmet with the human head to play with.
Moot point for the most part as the helmet is actually to protect the soldier from overhead airburst of artillery shells - hence the improvisation during WWI to include it in the combat uniform. Considering how a helmet of any description covers the top of the skull, the much smaller portion exposed to frontal fire is tiny compared to the amount exposed underneath - the human face.
No helmet we currently use covers that critical area. That was a consideration in the era of edged weapons but once gunpowder came into play note carefully that helmets actually came into disuse except for ceremonial purposes. It was the timed fuze and air burst applications which brought it back. The invention of the proximity fuze made it even more imperative as first rounds on target didn't need to be adjusted, they were on the mark.
Bullet penetration by other armed marksmen is actually the usual myopic thinking posed by any armed service - "how will our tanks do against other tanks?" thinking, when the actual application is "how will our tanks do ranging behind their lines wreaking havoc in their supply lines or command encampments?" The ability of helmets to resist ballistic penetration by some other soldiers bullet is symmetric warfare, note carefully those skilled warriors who practice asymmetric warfare do NOT wear helmets.
More often than not, they wear battle beards, which are as much protection as any helmet. : )
entropy
Member
Way less than M855 out of an A2 for me. I shot at 600 meters training for a post (Ft. Ord) rifle match. With my issue A1 and M193, I had about half the rounds go off the silhouette, or too low to score. With a borrowed A2 and M855, I kept them all in the "vital" area what would approximate the "C" area in an IPSC target. That still left me in the middle of the pack during the match.
C-grunt
Member
Id say that's more rifle than ammo. Last time I took my SPR(ish) rifle out to 500 yards was with M193. I kept rounds on my 2/3 sized IDPA steel silhouette about 9/10 times.
When I took my departments 40 hours patrol rifle class we had a day at the KD range. At the end of the day we were shooting at 300 yards on picture type targets and the "bad guys" had an A zone about 6"x10" across the chest. Using an ACOG and knowing my POI at that range I scored the highest that day by keeping about 15 out of 20 shots in that zone.
That being said not all M193 is the same. Just like M855. Ive shot some M855 with pretty good accuracy, but most times I've used it I got about 3 MOA.
Sunray
Member
Military hard hats are not and never were intended to stop any bullet. They're made for secondary frag and blast protection only. A Remington Yellow Jacket will go right through a standard M1 Helmet. Other hyper velocity .22 ammo will penetrate one side with no fuss too. Think it was at 100 yards, but I wasn't there when the lads were playing.
.45cultist
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The M193 breaks and peels at the cannelure, becoming unstable. The M16A2 was designed around the round, but rebarrelled for the longer tracer- 1-9 to 1-7.
PaFrank
Member
Major Culver lived through the development of the 5.56 and M16 platform, and while I will not attempt to try to repeat it, you can go look it up yourself on the Jouster web page. I forget exactly where it is on the site, you'll have to go searching for it..
http://www.jouster.com/forums/forumdisplay.php?2-Gun-Talk
http://www.jouster.com/forums/forumdisplay.php?2-Gun-Talk
lysanderxiii
Member
Incidentally, the specifications are only to provide a repeatable test to assure new manufactured ammunition has the same performance as the original SS109 . . .
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