MkII Grenades/ Why HE and LE fillers?

[Rhscott]

So like the topic, why were they using both High Explosive and Low Explosive fillings in the MkII grenades?  Cost?  Availability of fillers?  Storage concerns?  When did Low Explosive filling stop?

wondering?

[Kaptainssurplus]

https://tgrm.foxed.ca/Americangrenades/Mk II/The Mk 2 grenade.html

[Rhscott]

That is a good read.  So it seems “EC” smokeless powder was used due to shortages of TNT.  Interesting that it looks like both were black or gray till about 1926 when it says the HE ones were painted yellow.  Also seems about 1926 black became a “dummy” grenade color which seems pretty unsafe with all the previous made ones in black still in the system. 

So, by say 1935 both HE and LE grenades were supposed to be Yellow with only the shipping crate identifying the grenade as HE or LE?

 

color me confused with grenade colors from 1918-1940

[917601]

I don’t agree, WW1 until late 1944 smokeless powder was used exclusively, with M10 Ignitor fuzes. In late 1944 they went to TNT flake filled requiring M6 Detonator fuzes. 

 

The MKII performed satisfactory with much cheaper filler and much cheaper Ignitor type fuzes. Presumably , (no official directives can be found) they went the way of the WW1 75mm shrapnel artillery shell, bursting with black powder charge, a low grade explosive. When they switched to TNT filling, it becomes more effective with a high energy, high grade explosive shattering and propelling projectile parts/ pieces at super high velocities.

 

The TNT filled MKIi ( it will have an M6 marked fuze, shorter, fatter fuze train,  red sealant instead of green) is very, very much harder to find than a common MK II with M10 fuze. Research past posts.

[917601]

The article Kaptain posted for reference ( TNT mixture used with an M5 detonator type fuze ) in the early 20’s production was very low, very few examples of an M5 fuze exist. 

[Rhscott]

27 minutes ago, 917601 said:

I don’t agree, WW1 until late 1944 smokeless powder was used exclusively, with M10 Ignitor fuzes. In late 1944 they went to TNT flake filled requiring M6 Detonator fuzes. 

 

The MKII performed satisfactory with much cheaper filler and much cheaper Ignitor type fuzes. Presumably , (no official directives can be found) they went the way of the WW1 75mm shrapnel artillery shell, bursting with black powder charge, a low grade explosive. When they switched to TNT filling, it becomes more effective with a high energy, high grade explosive shattering and propelling projectile parts/ pieces at super high velocities.

 

The TNT filled MKIi ( it will have an M6 marked fuze, shorter, fatter fuze train,  red sealant instead of green) is very, very much harder to find than a common MK II with M10 fuze. Research past posts.

 

Thank you. That brief explanation has been more helpful than a hour of reading other on-line articles as you put it in perspective.  I was under the impression from other sources both LE & HE were just merrily being made and issued at the same time in pretty much the same quantities.  Your explanation makes more sense that due to cost and the LE ones working ok they were good enough till 1944.  That said, were all grenades painted yellow starting in 1926 just to put them under that same uniform color even if they were not actually High Explosive filled? This is what confuses me.

[917601]

The US ordnance color coding was just being developed prior to WW2. It wasn’t totally standardized till the 50’s.
 

Here is where we are today. Note the color Gold or Bronze isn’t listed but Gold colored ( I have a Gold colored WW2 81MM projectile and a Gold colored 155mm M121 VX shell dated 1991) signifies a complete round with NO energetic ( explosive) compounds loaded. Used for assembly/ disassembly, instructional, ammo feeding/ cycling/ loading drills.

 

By today’s standards, the yellow stripe on the flash powder filled MK II’s neck would be incorrect as the flash powder is not HE. Today, most black powder filled ( low order explosive) ordnance will have a Brown stripe. An example would be the spotting charge inserted into a practice bomb. While the bomb itself would be blue, or a blue stripe, ( training- concrete or water filled) , the black powder filled signal casing would have a brown stripe….another example are modern era Practice grenades, they had a Brown stripe on the neck, the body Blue, indicating it had a black powder spotting/ noise charge inserted into it.

[917601]

Also, do realize if doing “ restorations”, all these colors have a Federal Standard color, eg “F.S. XXXXX”. Most restorations when painted never look “ just right” to the trained eye because common rattle can spray paint was used. The FS paints are meticulously mixed, all the same. Testers modeling paints ( Hobby Lobby) have correct colors mixed up to the Federal Standard ingredients. 
 

For example, three , four different OD Greens were used in WW2. eg… Grenades had a specified FS color and number, Jeeps another, aircraft insignia, really fascinating on some WW2 colors….the regs actually stated by percentage the ingredients ….India black x percent, varnish x percent, linseed oil x percent, and keep in mind all the paints of that era were lead based, not acrylic or polyurethane based rattle can colors of today.

 

A trained eye can tell the difference by color, hue, texture ( sprayed, painted by brush, etc) , the study of the paint technology of that period is fascinating.

[917601]

More to illustrate the rather complex color coding system.

[Inertord]

On 3/7/2024 at 8:47 AM, 917601 said:

By today’s standards, the yellow stripe on the flash powder filled MK II’s neck would be incorrect as the flash powder is not HE. 

 

Please advise more related to MKII or MK2 Grenades being loaded with flash powder? First that I have heard of this in 40 years
 

Frank 

[917601]

EC smokeless powder, I refer to it as flash powder, my old age mistake. EC smokeless is a lower grade explosive which obviously doesn’t require “ detonation” to set it off, only a hot flame.