5.56x45mm effectiveness with expanding/fragmenting ammo?

[goon]

The complaints around the effectiveness seem to center around the use of either 55 grain FMJ out of too short of a barrel to fragment or with the SS109 which is designed to punch through stuff, meaning it will stay together.
What is the effectiveness like with something like a ballistic tip or a JSP bullet?
Does it bring it up to a more equal footing with the 7.62x39 or 7.62x51?

 

[GoRon]

Sounds like you might enjoy reading the Ammo Oracle.

 

[Aguila Blanca]

The complaints around the effectiveness seem to center around the use of either 55 grain FMJ out of too short of a barrel to fragment or with the SS109 which is designed to punch through stuff, meaning it will stay together.

Actually, you have it reversed. The current military issue is 62-grain, and the complaints are that the 62-grain out of a short barrel doesn't retain sufficient velocity down-range to cause the bullet to tumble and fragment upon entry.

The lighter 55-grain bullet retains more velocity and thus fragments more reliably, even though it carries less down-range energy.

 

[goon]

Thought that the 55 grain out of a short barrel was going slow enough that it soon dropped below some magic number velocity at which it no longer broke apart at the crimp cannelure.
???
Maybe I have been reading too much stuff on the net...

 

[Aguila Blanca]

This is taken from the Ammo Oracle article (I hope the format will come through)

Q. At what range will M193 fragment? How about M855?
Assuming true M193 or M855 ammo, velocity is the key. Velocity is dependent on barrel length and environmental conditions.

As barrel length increases, the bullet is propelled faster by the expanding gasses in the barrel, imparting more velocity on the bullet, resulting in a longer range before a fired bullet drops below 2700 fps. A shorter barrel imparts less velocity, and therefore the bullet has less range.

Temperature, altitude and humidity are other factors. As temperature or altitude increases, air becomes less dense and bullets travel faster. Contrary to common conceptions, as humidity increases air also becomes less dense and helps bullets retain velocity.

It is important, then, to keep in mind that any statistics given can only be approximate and can be affected by a wide range of factors. But as a baseline, these numbers are what you could expect for 75° F, 25% humidity, at sea level, from various barrel lengths:

Distance to 2700 fps | 20" Barrel | 16" Barrel | 14.5" Barrel | 11.5" Barrel
M193 . . . . . . . . . . . 190-200m | 140-150m | . 95-100m . | 40-45m
M855 . . . . . . . . . . . 140-150m | 90-95m . | . 45-50m . . | 12-15m

As you can see, barrel length and ammo selection make a major impact on fragmentation range.

Hmmm ... format is obviously less than optimal. In any event, the point is you need 2700 f.p.s. in order for the round to tumble and fragment upon striking the target. The M193 carries that velocity farther out than M855.

 

[goon]

Which brings us to soft point ammo or maybe ballistic tips...

 

[GoRon]

M193 is military ball 55gr

M855 is military ball 62gr w/steel penetrator

The most significant difference between M193 and M855 is that inside 100 meters or so M193 will yaw more quickly and fragment more substantially than M855. M193 also tends to be more accurate under 100 meters or so. M855, by virtue of its greater length, tends to catch up with M193 speed of yaw and degree of fragmentation outside of 100-150 meters or so. Unless you live in an area that is very open, flat, and not populated, the chances are far greater that you'll need effective close-range performance a lot more than the increased long distance performance that M855 is designed for. Remember also that even in large infantry engagements, the average range of engagement is less than 200 yards; 50 yards in jungle conflicts like Vietnam.

This is from the link I provided above in a previous post. It seems to agree with other sources. The 62gr out of the short barreled weapons doesn't seem to fragment reliably.

But the 62gr was designed to penetrate better through cars,vests etc..

 

[Smokey Joe]

The Box O' Truth

Suggest you visit The Box O' Truth website www.theboxotruth.com

They have a VERY interesting discussion of penetration in general, with and w/o fragmentation of the bullets.

 

[GoRon]

I love the box o truth

 

[goon]

The above source is very informative. Thank you.
Box-O-Truth is a cool site too.

 

[artherd]

The solution is the 77gr OTM loads!

http://www.ammo-oracle.com/body.htm#mk262

 

[Preacherman]

Take a look at the Hornady 55gr. TAP load. Plastic point, expands like the dickens (after all, it originated as a varmint bullet), and has rather less chance of over-penetration. The down side is that penetration may be less than optimal on a heavy-set person or through thick clothing, but then, that's what follow-up shots are for...

 

[Nightcrawler]

I found the Box 'o Truth to be very enlightening. Especially consdiering the claims of AR-15ers all over the internet regarding magic fragmenting 5.56mm bullets. Most only point to those same pictures of 5.56mm fragmenting in jell-o and have never done any actual tests.

Turns out it'll still go through a wall. Just like you'd expect a high velocity rifle cartridge to do...

 

[benEzra]

But the 62gr was designed to penetrate better through cars,vests etc..

Better penetration at extended ranges. 55-grain M193 penetrates better in the 0-200 yard realm due to the higher initial velocity, but 62-gr offers better long-range penetration because the heavier bullet means more retained velocity at long range.

 

[rbernie]

The solution is the 77gr OTM loads!

What does OTM stand for?

 

[JShirley]

Open-Tip Match

 

[Bottom Gun]

I load my own hunting and varmint ammo and have had excellent results with the 64 gr Winchester Power Points in a 16" barrel out to 350 yd.

 

[artherd]

I found the Box 'o Truth to be very enlightening. Especially consdiering the claims of AR-15ers all over the internet regarding magic fragmenting 5.56mm bullets. Most only point to those same pictures of 5.56mm fragmenting in jell-o and have never done any actual tests.

Turns out it'll still go through a wall. Just like you'd expect a high velocity rifle cartridge to do...

The Box 'o Truth tests are nice for what they are, a totally uncontrolled test with little to no scientific method and no controls.

http://www.theboxotruth.com/docs/bot12.htm 5.56mm was the only round that fragmented and was *sometimes* stoped by their 4th wall.

Of course high velcoity rifle cartridges penetrate a wall! Even several! But you can't deny the anecdoctal evidence that all pistol cartridges exited cleanly, while *some* .223 was stoped. By 4 dam walls. KNOW your target.


Now, I'd like to see what a .223 (and for that matter a .308) frangible round would do to a setup like box 'o truth! 1 wall and then it's sandblasting #2? That'd be neat.

 

[Nightcrawler]

They did test 5.56mm frangible ammo. It began to break up, but still made it through to the 4th wall.

Which is to be expected. But to listen to some tell it, 5.56mm ball will pierce a helmet at 1300 meters but won't make it through two layers of drywall and plaster It comes from people just repeating what they read. That's where my gruff comes from.

 

[Aguila Blanca]

Better penetration at extended ranges. 55-grain M193 penetrates better in the 0-200 yard realm due to the higher initial velocity, but 62-gr offers better long-range penetration because the heavier bullet means more retained velocity at long range.

Don't forget that the military 62-grain bullet, the M855 round, also has a hardened penetrator core at the tip -- which the 55-grain M193 does NOT have.

 

[longhorngunman]

I'm using the Hornady 55gr TAP load after my own "redneck testing" on sheetrock, wood doors, and water jugs. I't is true that while the 55gr FMJBT military load may fragment in jello and animal tissue, it goes through many walls and 6 inch thick tree trunks with ease . The TAP load would penetrate two 1/2" sheetrock panels but was fragmenting on the way out and would only imbede itself in the surface of a wooden door behind it. People say use a shotgun and buckshot for home defense, uh no, the 00 buckshot would go clean through the sheetrock and through the 2 inch thick wood door behind and keep going, heck, the WAD went through both layers of sheetrock . Tried 9mm, and 40S&W handgun loads they also went through the sheetrock and wooden door. Least penetrative loads I found were the Hornady TAP(which would totally disentegrate a full water jug upon impact) and 12ga #8shot dove loads( which also went through both layers of sheetrock before imbedding into the wooden door behind.

 

[444]

I never conducted any of my own penetration testing of ammo. But, one thing to keep in mind: this box of truth guy (if I remember correctly) is a retired guy conducting these tests in his back yard with homemade equipment. His results contradict the testing done by some recognized experts in the field of ballistic research.
That may or may not mean anything.
One thing I think it does mean is that many people on the internet come across something that supports their own point of view and advertise it as fact. And pretty much everybody can find something to support their beliefs somewhere.

 

[Aguila Blanca]

The solution is the 77gr OTM loads!

http://www.ammo-oracle.com/body.htm#mk262

Except for one minor problem -- twist rate:

There is, of course, an exception: if you want to use loads utilizing the heavier, 75-77 grain match bullets currently used by Spec-Ops troops and other selected shooters, you'll want a 1:7 twist barrel. Although military loadings using these bullets are expensive and hard to get, some persistent folks have managed to obtain a supply, and will need the proper barrel twist to use them. Anyone who foresees a need to shoot this ammo should consider a 1:7 twist barrel.

 

[rbernie]

this box of truth guy (if I remember correctly) is a retired guy conducting these tests in his back yard with homemade equipment. His results contradict the testing done by some recognized experts in the field of ballistic research.

Well, he's not exactly doing this in his back yard, but the point is valid - he's not 'an expert'. But does that invalidate what he's documented? He's been doing this for a while, and I've not seen anyone that could point to fundamental issues with his approach.

He's not claiming that somehow his test medium better duplicates human physiology better than ballistic gelatin. In fact, the reason that I like the BoxO'Truth is that he's not claiming anything at all other than exactly what you see - this is what happens when you shoot a particular round into a bunch of wood, drywall, and water jugs. The rest is an exercise for the reader.

One thing I think it does mean is that many people on the internet come across something that supports their own point of view and advertise it as fact. And pretty much everybody can find something to support their beliefs somewhere.

And therein lies the rub. Remember what Mark Twain said - lies, damn lies, and statistics.....

But back to the point here - the BoxO'Truth is actually not a terrible test of the ability of specific rounds to penetrate modern building materials. In fact, I'd wager a guess that there is not much in the 'expert' world of ballistic gelatin testing that will simulate that specific issue as closely as the Box O' Truth.

If someone is silly enough to extrapolate that data into how a round will perform on human physiology, well then they're just as misguided as those who would look solely to gelatin tests to determine how a round will behave when shot through wood and drywall and masonry.

 

[Smokey Joe]

Well Said!!!

RBernie--Well Said!

There's nothing wrong with "scientific" work by white-coated PhD's. There's ALSO nothing wrong with home-made experimentation like that on The Box O' Truth.

What's wrong is when someone ELSE takes what is shown as gospel, and/or extrapolates it far beyond what has been proven, or claims that the case in point proves/disproves/invalidates other work.

Serious investigation compliments other serious investigaton.