Fragments and hit probability

Does anyone have any examples or pictures of grenade fragments?
I am looking for results from any design that uses a notched steel coil for it's fragment load (like the American M-26 or British L2).
I've been researching hit probabilties on various grenade designs and how they compare to the actual wounding capability (based on the weight of the fragment and the number of hits).
It's suprising how much more effective pre-formed fragments are.
An oddly similar effect was noticed when various groups tested something they called "DIME" (Dense Inert Metallized Explosive)- powdered tungsten mixed in with the explosive- a fast whirlwind of white hot tungsten dust that was so light, it couldn't fly past a few meters, but was "unpleasant" when encountered at close range.
Took an interest in this after a grenade bounced off my helmet some months ago, and then dudded out.
Any pictures of grenades with notched coil or pre-formed fragments, along with measurements of the frag would be helpfull.
Thanks to all in advance!

Grenade bounced off your helmet??,good grief!:afraid:


waff

My thoughts exactly Waff, a very lucky guy and i take my hat off to you E- tech.
Ime no technical expert but i hope it dosnt happen again. Welcome to the forum, ime sure there are a few guys n gals who can discuss this with you.
Ime only into Mills grens, if only they had designed the segments, internally, perhaps they would have done a better job. However i am open to the suggestions of the hows and whys of this.

Andy

V

Hi,
Go for a walk here:
http://history.amedd.army.mil/booksdocs/wwii/woundblstcs/default.htm

From what I've read, the serrations were placed outside to help cause a well-patterned break up of the grenade body. After high-speed photography was invented, and it was shown that the serrations didn't help, then they were retained because it was believed that it would help the soldier get a secure grip on the grenade in wet or cold conditions.
After exsisting supplies were spent in the Korean war, the M-26 was brought along with it's internal fragmentation coil. Ideally, the M-26 and the L2 should break up into about 1,150 fragments weighing about 130mg each. This gives a hit performance of about 3.7 fragments per sq.meter at 5 meters from the boint of detonation, and only 0.9 fragments per sq.meter at 10 meters from the grenade. The weight of the fragments should give about 86 Joules of energy per fragment.
The DM51 grenade uses 6500 steel ball bearings (2mm dia) that weigh 0.035grams. They give a hit performance of 20.7 fragments per sq.meter at 5 meters distance, and 5.2 fragments per sq.meter at 10 meters distance from the detonation. The DM51 has much lighter weight fragments, but the increase in the hit probability increases the chance for a disabling wound.
The grenade that hit the back of my helmet was an old F-1 thrown from a nearby window while I was running my robot. Usually they threw them at the robot in this particular neighborhood- this time, the thrower got ambitious. Lucky for me, moisture got into the fuze. The grenade I threw back (my M203 helped my throw) did not dud out, however.

Frags

Heres a pic of some frags from the L2A2 and the new L109A1 British grenades collected from the wooden wall of the gren range. as you can see the coil doesn't always break up into individual squares. Likewise the pimples inside the L109 are nearly always in groups rather than individuals.
cheers, Paul.

are these pics any interest to you fragments from M9219A2 HE DP 40mm rifle grenades,these were the biggest pieces we came across

Thank you all for the links and pictures- they have been very helpfull!
Those 40mm pictures were a real eye-opener- I expected better performance from those little things- those big chunks will lose velocity too fast, and there isn't enough of them at that size for a decent chance at a strike!
I knew the pieces of most grenades don't break up predictably, that is why pre-formed frag is so much better.
The 40mm grenade I sent through that window seemed to have functioned as designed- it hit the opposite wall from the window and showered the guy's head and shoulders with frag about the size of a piece of rice. He would have been better off using the AK he had laying next to him- lucky for me, he didn't!
Thanks again, and keep 'em coming if you find any more! I may get to a grenade range myself in the next month or so- I'll share whatever I can find!

I have a picture of the No 36 fragment breakup that I will endevour to find. I have done a little work in this and been involved in a few comparison activities between different grenades, including a quick historical analysis a few years ago. Hit probability (essentially a function of number of fragments) is only one issue, the other issue is the energy of each fragment and the intent of the grenade - kill by blast, kill by single fragment or kill by multiple fragment strike. All these are taken into consideration when a grenade is designed. Larger fragments (No 36, M26) have good lethality when they strike but oflen have only limited fragments which will reduce effect. Many modern grenades use a matrix of preformed fragments so the distribution and size of the fragments is controlled. The problem is that the smaller the fragment the sooner it looses its energy and the smaller the lethal zone. While this is sometimes desireable it can mean that the grenade is less effective than desired. The last thing I will also say is that a battlefield kill does not mean that you actually kill the opposition, simply make him ineffective to do his job in the current engagement. For infantry this can mean putting him out of action for only a few minutes until you can secure his location or engage him at close quarters. If you are attacking a rear area (ie by Artillery) you actually want something more permanent as the neutralisation of logistics or indirect fire assets necessitates a longer term solution because you are trying to neutralise their effect on the battle which has long term implecations (you don't want them reconstituting quickly).

Very true- number of fragments controls the likelyhood of a strike, the weight and velocity of the fragment determines it's wounding ability. I have yet to see a hand grenade using preformed fragments that had fragments larger than 3mm diameter steel balls (weight; 120mg. giving 86.4 Joules of energy at 1200 meters/sec. velocity.)
Other than keeping the grenade's weight low, I figure the small frag is used for it's good hit probability (more smaller frag, rather than fewer large pieces), and short wounding distance- allowing an assault to keep moving forward.

more Frags

Heres a selection of frags from cast iron grenades. as you can see some are BIG !

so strange that the mills/pineapple design stayed around for so long- only about 55 grams of explosives (either "e.c. powder" or TNT), propelling those big chunks of iron! Yes, you'd kill whoever got hit by THAT size of a fragment, but the odds of hitting someone had to be pretty low.

Here is a link that shows a US M67 grenade low order detonation and cut away;

http://www.big-ordnance.com/grenades/grenades4.htm

Thanks for the link, Alan. My boss has a similarly low-ordered m67 on his desk from a range clearance operation done last year. I saw a few M67's used in Iraq. Too bad everything was moving a bit too fast- I couldn't take the time to collect some fragments from them. Ah well- more range time is coming up, and someone ALWAYS forgets to pull the pin, or the jungle clip, so I'll get a call, if I take my time, I should be able to collect some fragments. From what I've read, when an M67 high orders, a good half of the fragmenting body is turned into a metal powder that is pretty much useless. I've always wondered how much of that frag pattern on the inside actually works like it's supposed to.

Hi guys. I'm new. :tinysmile_twink_t:


Found this picture of a before and after No.36m a few years ago. Not sure of circumstances or conditions. Might be relevent to the thread.

Some more fragment examples from a US army medical site. [Be careful, some very graphic stuff here. If a link says something like 'Traumatic decapitation'... it won't be pretty.]