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Help with Grenade Opinion


cerick1450
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Dirt Detective

This post has info and pics of the M10A3 fuze in a practice grenade.

 

http://www.usmilitariaforum.com/forums/index.php?/topic/262043-wwii-grenade-question/

 

Smitty

 

Its my understanding...the M10A3 fuse shown in fig. 229 in the practice grenade is the same as fuze M10A3 in fig. 222 ...in your post above ( post #17). the only difference is the practice grenade had no explosive filler except a small blak powder charge and a hole in the bottom with cork.

 

In other words..I thought in WWII and before..they didnt make practice fuzes's they just used what they had without any explosive filler and leaving the screw out of the bottom...

 

Mike

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Yes, you are right. The M10's and M205s were used in practice grenades. The M10s pulled double duty of sorts. First you must understand there are two types of fuzes. An Ignition fuze and a detonating fuze. There was a MKII that was filled with 3/4 of an oz of EC powder or smokeless powder. The M10A3 was issued with this type of MKII. Some refer to this as the MKII A1 fragmentation grenade. This type of grenade didn't use the high power detonating cap because the grenade detonated like a pipe bomb. The powder inside produced enough pressure to cause a "mechanical" break down of the grenade. Pressure built up, grenade came from together. Same principle used in the pressure cooker IED's in Boston.

 

Its sound confusing, to understand it, (my apologies if you know this already) you have to know the two types of explosives and how they work. An explosion is something burning at or higher than the speed of sound. Think of the old west movies when the black powder is laid out and the cowboy puts a match to it and it starts to burn. Black powder falls in to the "Low Explosive" class. For "High Explosives" this same thing is happening, but way faster. C4 detonates at around 3,200 feet per second. (C4 has a TNT equivalent ratio of 1.4. TNT is used as the base to gauge explosive power. So it takes 1.4 pounds of TNT to equal 1 pound of C4.) As the burn breaks the sound barrier, you get the boom. The damage is caused by the gases produced with no place to go. For HE to get to the proper velocity of detonation, it has to be "hit" with an explosive train. To achieve the right velocity, very sensitive explosives are arranged in a specific order in a cap from most sensitive to least sensitive. The explosive train is initiated by electricity or flame which ignites each of the mixtures successively (Lead Azide and Mercury Fulminate are most common) at a high rate of giddy up. By the time the explosive train reaches the end of the cap, its burning/moving fast enough to detonate the HE it is in contact with. The M10A3 doesn't detonate "fast enough" so it used to ignite fillers in the MKIIA1 and other practice grenades.

 

So visually the cap is not as beefy as a detonating cap use in an HE grenade. Look at this xray of an M67 with what I would assume is an M213 fuze next to the picture of your fuze. Its grainy but you can clearly see the difference in the detonating fuze and an M10 used either in a practice or EC frag grenade. The reality is that most fuzes you will find are practice because after a frag grenade goes off, there isn't a lot left. With the practice fuzes, the remove it from the grenade and toss it and put a new one in.

Presentation1.pdf

post-162205-0-68100400-1484251036_thumb.jpg

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Dirt Detective

MKII's and MKIIA1 filled with EC blankfire powder would be correct to have the M10A2 or M10A3 ignition fuze as shown in post. If it was filled with TNT then it would have M6 detonating series fuze. We dont know what this grenade was filled with so to say the M10A3 fuse is wrong for this grenade..I respectfully disagree.

 

Here is a picture of an original MKIIA1 frag box with the M10A3 fuze marked on it.

 

post-2677-0-61898100-1484262806_thumb.jpg

 

Maybe im missing something.

 

Also when WWII grenades with the M10A2 and M10A3 fuze exploded the fuze stayed intack and generally was only damaged if it hit something hard.

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We are on the same sheet. You haven't missed anything. We both are correct. I am basing my opinion on the fuze being practice on my 20 plus years of EOD experience. I agree with not knowing the filler. We can only guess. I never said the M10A3 fuze was an improper fuze for this grenade, just said it was a practice fuze. Based on my experience, most fuzes encountered in the civilian world are practice fuzes, or fuzes used in practice grenades. The spent grenade fuzes are easy to come by because after you throw them, you go pick them up. So even though this fuze can be used in a frag grenade or practice grenade, in my opinion it was use in practice.<br /><br />You are right about the MK series grenades fuzes sometimes staying intacked. The fragmentation pattern was unreliable in all MKII grenades no matter what fuze or filler. Thats why the lemon grenade (MK26) used a notched frag coil and a sheet metal body to produce a more uniform pattern than the MKII. most MKII frag is produced from the middle and the top and bottom fly at a high rate of speed. Your fuze is in very good shape and doesn't appear to have flown at a high rate of speed, this also supports the used in practice opinion. I could be wrong, but I am pretty sure.<br /><br />I responded to an EOD emergency call in Georgia involving my 1st MKII grenade in the early 90's. The Police officer who called told us his grandpa died and he had a grenade in his sock drawer. He said as a kid he thought his grandpa was cray because he always threatened to blow him up with his hand grenade. He had no idea he really had one till he died. LOL!<br /><br />Smitty<br /><br /><br /><br />

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Dirt Detective

I never said the M10A3 fuze was an improper fuze for this grenade, just said it was a practice fuze.

 

Fair enough smitty..I just didnt want WWII collectors to think the M10A3 fuze wouldnt be correct for their MkII or MKIIA1 frag on display.

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Dirt Detective

Based on my experience, most fuzes encountered in the civilian world are practice fuzes, or fuzes used in practice grenades. The spent grenade fuzes are easy to come by because after you throw them, you go pick them up. So even though this fuze can be used in a frag grenade or practice grenade, in my opinion it was use in practice.<br /><br />You are right about the MK series grenades fuzes sometimes staying intacked. The fragmentation pattern was unreliable in all MKII grenades no matter what fuze or filler.

 

 

I have seen hundreds of spent MK10 fuzes and all were from exploded frags...some had dents on the bottom some didnt. I am only talking about the MK10 fuze and some M6...I have no opinion on others of post WWII vintage.

 

Look how well the neck of a MKII stayed together..the blast got weaker as it went up and the fuze stay's together very well unless it hits something hard and is then smashed.

 

If someone has a MK10 fuze with dents on the bottom..its from an exploded frag. I will try and post some pics showing the dents from the explosion.

 

These MKII's are really a neat addition to a collection..wish there was more written about them.

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I like discussions like this!!! The MK II is a iconic part of history. I collect old obsolete publication on ordnance and ordnance items. I have a couple of hundred gigs of stuff and tons of hard copies. I will dig and see if have any test data on the MK II. I have some on other grenades. It's cool how they function. The inconsistency in the frag production was, I read and it makes sense, due to the casting process. Like you said, the grenade fuzes some time stay in tacked. The document I read (readers digest version) as the blast wave radiated out from the center of the grenade, the flaws in the casting (air bubbles, micro cracks, etc,) combined with the inconsistency in the explosive filler (air pockets, etc,) caused the grenade to come apart in large chunks. It even said the the base and fuze would shoot out. I hate to be in the path of the base as flew!! LOL! The consistency of the filler is still an issue to day. More so in the IED world. When in Iraq, we would conduct post blast investigations on EFP strikes. EFP is an Explosively formed projectile. They were extremely effective, but could of been a lot worse if the bad guys new explosive fundamentals. The EFP is a poor mans sabot round. It uses the mizeny chardine effect (SP?) It launches a ballistic disk that uses kinetic energy to defeate armor. The US uses this same principle in TOW II Bs. Where this ties in to the grenade and explosive consistency is in the packing of the explosives behind the disk. Explosions travel in waves. It radiates out from the point of initiation, knowing this we can focus the wave to do more with less. Shape charges are an example. A PG-7VL has a 93mm diameter and can penetrate half its diameter or more through rolled homogenous armor. This uses the Monroe effect. In the EFPs the bad guys would pack the explovise in and the air gaps caused an irregular blast wave that impacted the ballistic disk. The effect on the disk caused it to sometimes break up as it was being launched, seriously degrading the effectiveness. This is similar to the isues with the MKII. Flake TNT detonates slow, and inconsistent which produces an irregular blast wave the wave hits some parts of the grenade before other and the flaws in the casting are amplified because they come appart at diffrent times. It happens very fast. I have done I t again, I can ramble, but I like this stuff! LOL! If I can find the data, I will send it to you along with some other grenade reference material to help you with your collection. If you have any other ordnance you want info on, let me know and I will see what I got.

 

Smitty

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Ok, my discussion with dirt digger has prompted me to do some research. I see a lot of questions about proper combinations and what era a MKII grenade is from. I combed through my stuff and I put together this stuff to help grenade collectors. I am going to focus this post on the MKI and MKII. I am doing this because they are closely related and I will include some interesting facts that prompted the evolution of the popular “Pineapple Grenade”. This the chronological order as pulled from books and publications.<br /><br />Terms:<br />Bouchon: This is the die casting that holds the firing mechanism. The upper has the mechanics (striker, striker spring, hinge pin, lever and cover. The lower part has the primer fuze and detonator.<br /><br />The MKI was used during WWI. The US didn’t have a good grenade and was using the British mills bomb, the French F1 and few others. The Trench Warfare Section designed the MK I and shipped overseas in 1917. MKI bodies were made of a soft Iron, had a filler hole in the bottom closed by a plug. Normal color was black with a paint dab on the plug to ID the filler. Fillers were 2 oz of TNT or Trojan Grenade powder. It was a failure of sorts. The MKI was condemned because of the complication of operation. The arming of the MK II fuze took 5 steps to arm. There were several cases of Soldiers throwing the grenade and not completing the arming. The Germans would pick it up, complete the arming and throw it back. (MKII fuze was used on all US grenades during WWI) The MK II fuze is easy to recognize, it has the funny looking narrow spoon and separate cap. In 1918 all use of the grenade was stopped. In late 1918, the MKII was designed to replace it.<br /><br />Makers of the MKI include the following Caskey-Dupree Co. of Marietta, Ohio (experimentation, development and production) Gorham Manufacturing Co. of provenance, RI (production)<br /><br />The MKI and MKIA1 training grenades were solid bodies. The only difference is the A1 had a pin.<br /><br />By Dec of 1918, 21 million MK II grenades were produce. The crazy part is according to records only 516, 533 were actually sent overseas. Wow!!! The first of MKII’s used the remaining MKI bodies. When exhausted, they used a slightly redesigned body made of cast iron. The change was a more tapered body, a flat base, and slight groves on the neck/top cone. Still had a threaded hole in the bottom for filling. Early MK II were painted with a non-acid black paint or a transparent varnish. The upper part was dipped in an anti-rust compound and asphaltum (no idea what it is, it may be an anti-seize or waterproofed sealer) is coated on the threads of the fill hole and fuze well. When loaded, the grenade was painted grey or had a grey paint mark on it. This grenade was called: Grenade, Defensive, MK II. It used the M1 fuze. Grenade and fuze were shipped together.<br /><br />Companies involved in MKII production were: Caskey-Dupree Co, Spacke Machine & tool Co, Stewart-Warner Speedometer Co, Miami Cycle & Manufacturing Co, American Radiator Co, International Harvester Co, Doehler Die Casting Co, and Precision Castings Co.<br /><br />Next modification made the Grenade, Hand, Fragmentation, HE, MK II. It used the M5 fuze. Grenade and fuze were shipped separate. Fuze well had a wooden shipping plug. Grenade was painted yellow and may have a letter stamped in the side showing who made it.<br /><br />The next version kept the same name as the last grenade. The body had minor changes. The groves were deeper and the taper was less and the base was flatter. The filler hole was tapered with a 3/8 in tapered pipe threads and closed with a die cast plug. It was filled with the EC Blank fire Powder and used an M10 series fuze. Initially, the body was painted the same as the previous version. In 1943 the color scheme changed. The grenades after 43 were painted olive drab with a yellow band. This grenade was shipped with fuze installed.<br /><br />The Grenade, Hand, Practice, MKII used a standard MKII body. The obsolete MKII and M5 fuzes were used for practice grenades until they were all used up. Then the M10 series fuze was used with the addition of a small charge to produce a report. (M10 fuzes were ignition fuzes, the MKII and M5 were detonating fuzes) The small charge was black powder in a cloth bag or paper tube. A cork was used to hold the charge in place.<br /><br />The next version is the Grenade, Fragmentation, MK 2A1. This was used in late WWII, Korea, and early Vietnam. This version has no filler hole in the bottom. Originally it was filled with EC Blankfire powder and used the M10A2 or M10A3 fuze. The filler was change later on to use flaked and granular TNT. The TNT required a detonating fuze. The fuzes used were the M6A4C, the M204A1, and the M204A2. The grenade was painted olive drab with a yellow band. Grenades were shipped with fuze installed.<br /><br />Smitty<br /><br /><br /><br />

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Dirt Detective

Here are some pics what the grenade fragments looked like and markings all bottoms seen were the solid bottom.

post-2677-0-28640600-1484538070_thumb.jpg

post-2677-0-72784100-1484538086_thumb.jpg

 

Notice there are 1, 2, 3, and 4 segments...the Army wanted more smaller pieces.

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Dirt Detective

Close up of markings..I assume some are mold markings as well as makers mark like AF, for American Fireworks. Along with a sheet steel target. As poorly as these were said to explode I would not want to be in an enclosed room when one went off.

post-2677-0-18022800-1484538198_thumb.jpg

post-2677-0-65263200-1484538241.jpg

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Dirt Detective

here is a cool pic....notice the solid bottom. A empty body was weighted and then a number of fragments were added to match the grenade body's weight.

post-2677-0-81207800-1484538434_thumb.jpg

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Dirt Detective

Here is a pic of what a WWII hammer pin and spring look like compared to the post war type..not sure when that change occured..but if you have a WWII grenade fuize ...it should look like the bottom set.

post-2677-0-45657500-1484538889_thumb.jpg

post-2677-0-18679000-1484538896_thumb.jpg

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Dirt Detective

Hi Smitty,

What is the ignitor in the end of the M10A2 fuze...that the bickford fuze ignites? All I can find is it says igniting charge. Nothing that says what it is.

Also..what is the material in the detonating charge in the M6 fuze ?

 

Thanks..

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The M5 fuze use a commercial No. 6 detonator/blasting cap that contains 15 grains of mercury fulminate. Here is an ATF document with info on the No.6.https://www.atf.gov/file/21986/download My books say 15 grains the ATF say 1 gram. I guess its about the same.

 

The M10 series fuze is an igniter fuze uses the bickford time fuze the A1 had an problem as was deemed unsafe. The A2 and A3 had two compressed black powder pellets at the end. The difference in the A2 and A3 is length of the bickford fuze which changed the delay time. A2 was 4.3 to 5.5 seconds and the A3 is 4 to 4.8 seconds.

 

Smitty

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  • 7 months later...
Garandomatic

One strange thing about these Burnham grenades I'd that they often seem to be numbered on the bottom. I've got an unfinished iron body now, too, and it is numbered, as well as an ashtray undoubtedly made from a Burnham grenade as it was a local find, and it is numbered as well.

 

Cerick, if you ever decide to part with this one, let me know.

 

The local book doesn't have a ton of info on the production, to answer an earlier question, just a smattering of "this is what the town did in the war" content.

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The following is from my notes. It would seem to indicate that the M10A3 fuse could be used on either MKII or practice grenades.

 

 

M10 Igniting Fuse - Includes M10, M10A1, M10A2, M10A3. This fuse gives a delay of 4-5 seconds and is designed for use with grenades having fillers that do not require a detonator.The M10 fuse body was styled the same as previous fuses and required the use of a fuse sealer. The M10A1 was declared unsafe for use due to the flame bypassing the Bickford fuse and igniting the charge directly. The M10A2 remedied this. The delay element on the M10A2 is cut to burn 4.3-5.5 seconds, the element in the M10A3 from 4.0-4.8 seconds. This fuse may be found on MkII, Mk2A1, MkII Practice an d M30 Practice.

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I got the following from my notes. It would seem to say that the M10A2,3, fuses could be used on either MKII's or Practice grenades.

 

 

M10 Igniting Fuse - Includes M10, M10A1, M10A2, M10A3. This fuse gives a delay of 4-5 seconds and is designed for use with grenades having fillers that do not require a detonator.The M10 fuse body was styled the same as previous fuses and required the use of a fuse sealer. The M10A1 was declared unsafe for use due to the flame bypassing the Bickford fuse and igniting the charge directly. The M10A2 remedied this. The delay element on the M10A2 is cut to burn 4.3-5.5 seconds, the element in the M10A3 from 4.0-4.8 seconds. This fuse may be found on MkII, Mk2A1, MkII Practice an d M30 Practice.

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