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Discussion Starter · #1 ·
I have a nice post war 81MM mortar in my collection,it has the little tabs for the powder bags and I would like to replicate them for display,it would be nice to have them to help explain how they work when I do my school displays.
I have looked online but have been unable to find an actual picture of the bags, everyone refers to them as "tea bags",so I assume they were much like an actual tea bag.
If anyone has a good example or even a good picture I would really appreciate it. Thanks.
 

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The crescent shaped charges are a "New Army" contraption. It's been almost 50 years since I had a Weapons Platoon with a section of 81mm mortars. But, the above picture is what I remember. At the end of the day, we'd spread the removed and unused charges out in a demo pit to burn them. We were still firing WWII produced HE rounds in the 1970s. The charge tables included in the crate were approved by George C. Marshall. I might still have a copy in my papers.
 

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A lot will depend on the age of your setup. In WWII they used the cello wrapped bags of sheet powder that clipped into the holes in the fins as shown in the TM. Later on they went to little fibre bags in a partial ring shape that fit around the fin tube. They have actual powder in them rather than the extruded sheet stock and later they went to synthetic fiber bags shaped to fit around the fin tube. I'm sure you'll want to get the type proper for your gun.

Frank
 

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Discussion Starter · #10 ·
I was able to find a 1967 date on the piece between the fins and the body,the place were the powder bags were located.
I would prefer an actual WW2 model but complete mortar rounds are hard to find!
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We were still firing 81mm Illum rounds in the 90s with cotton increment bags.

All the ones on HE I saw were some shiny treated, almost tyvek-looking white material/paper.
 

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I'm guessing now you have the mortar bomb and not the mortar? Doesn't really matter in the end. The bomb you have pictured is a much newer type and would have used the donuts. Like Crapgame pointed out they could be fabric or plastic. With the version bomb you have pictured either could be just fine.

Frank
 

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The rounds we fired in the 70's and early 80's had the increment bags marked chg B. I incorrectly assumed it meant comp B. They were a cellulose bag about an inch wide and long enough to fasten to the tabs top and bottom. If I remember right, they were sewed closed top and bottom. We never fired a full charge so we always had a lot of leftovers to burn. I pulled one apart and the charge looked like shotgun flake propellant. The kept issuing us, I believe it was the M374 round wtih the 526A4 fuze for the HE rounds that had serious safety issues. Originally nick named the Rice Paddy round because of the super quick fuze that would explode on the surface and not bury itself in the bottom of the rice paddy. They found out later that it sometimes armed when it hit the bottom of the tube instead of inflight. That made extracting a misfire hazardous.
 

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Discussion Starter · #15 ·
I'm pretty sure the "increments" I need for this round are the ones pictured in the manual picture from belt frog,it is labeled "M5 Increment for 81MM" I just need to find some kind of material that looks like tea bags,fill them with "black beauty sand blasting material and have my wife sew them up!
 

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Yes, that is the style you need. Your round is an M374 HE. With the tapered section between the body and fin, they were designed to use the cloth powder bags attached with clips. Later versions had a straight turned section of the tail boom and those used the C-shaped snap on propellant increments.

The M374 had a "Charge A" bag that wrapped in a spiral around the tail boom. Then the "Charge B" increments were clipped on over it and were added or subtracted depending on the range desired. A minor correction to Cobb's post above.....Charge B, not Comp B. Comp B is the explosive inside the body. The increments were filled with smokeless propellant powder.

I'm not sure of the material used for the bags. In WWII the standard was raw silk but these look like plain white cotton. They measure 1 1/4" wide and 5 3/4" long. Each end has a 3/8" slot with button hole stitching for attachment.

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Discussion Starter · #17 ·
That is just what I have been looking for! It was hard to tell what king of material the bags were made from from the TM drawings.
Are those bags a thin material or thicker like a T shirt type stuff? And how was the inner bag attached? Did it just use the same clips the B bags used?
I really appreciate this info,it's been driving me nuts searching online and not finding the pictures like the ones you posted!
 

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The material is thin, about like the feel of a pillow case. The "A" charge is held on the same way with the top and bottom clips. I don't know how long it is as I didn't want to remove all the "B" charges to unwind it.

I know some of this type of info is obscure and hard to find. Glad I could help.
 

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The powder used in WWII and possibly up into vietnam was basically the bulk grade of bullseye. I don't recall what the current stuff is but it isn't much different.


Frank
 

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Discussion Starter · #20 ·
I'm just going to use some of that black sandblasting material to represent powder,it's just for display, for launching rounds I use a 12 gauge black powder round!
 
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