DIY Smokeless Powder - No. 7 Smokeless Powder Manufacturing
No. 7 Smokeless Powder Manufacturing
Manufacturing the No. 7 Smokeless Powder formula seems to be fairly straight forward. There are only 4 “Chemicals” Necessary. My Test sample was produced in a very small laboratory batch. Instead of Willow Charcoal; I used the black charcoal leftover from night time fires in the wood stove retrieved from the ashes in the morning after the fire had burned out overnight. The ratios by weight are listed below for my first test batch:
Potassium Nitrate KNO3 2.1 grams 32.4 grains
Ammonium Nitrate NH4NO3 7.14 grams 110.2 grains
Willow Charcoal C 2.10 grams 32.4 grains
Lead Nitrate Pb(NO3)2 1.720 grams 26.54 grains
My source reference is on page #35 in PRIMERS for Small Arms Cartridges by M. J. ALBERT and H. F. OELBERG, Copyright, March-1944. A pdf copy is available at: https://www.aardvarkreloading.com/re...%20Oelberg.pdf
There are two process methods discussed for making No.7 powder per the reference. One is to mix and heat until the entire mixture is reduced to a solid, then break it up into kernels/powder (similar to black powder production). The second is to make the mixture and when it is like a past dough; either squeeze it out in a round strand pasta press – or to roll it out and run it through a pasta press with ribbons similar to Angel Hair pasta. The powder strands are then cut to length similar to extruded powders (stick) powders.
For my initial testing I wanted to try to replicate a “Stick Powder” as it reportedly exhibited more desirable burn characteristics and pressure generation similar to the Smokeless Powders of that day.
Manufacturing Process Steps:
1. Individually weigh elements in grams (or Grains) according to the weights previously listed for each chemical.
2. Mix the Charcoal with an equal Volume of water (not by weight). My charcoal I made was ground in an electric coffee grinder, resulting in an extra fine charcoal powder.
3. Ensure the Ammonium Nitrate (usually prilled) is finely ground, as well as the Potassium Nitrate, and Lead Nitrate. Mix all three together in a separate container. When well mixed; add them dry to the Charcoal mix in #2 above, and then add water to volume of the three final chemicals.
4. Stir the 4 chemicals; original directions call for “Cooking/Heating” the solution until dry and hard - then break up or grind the hardened mass.
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Making the No.7 Powder - 1st Experiment
I deviated from the original instructions in a couple of areas.
a. My charcoal was derived from charcoal left in the wood burning stove each morning, wood was predominantly soft pines with some medium hardness Larch trees. Ground in an electric coffee grinder to a very fine powder.
b. The mixture I attained when following the instructions resulted in a very wet mixture. I had mixed the Experimental batch in a shot glass. Left it to air dry for 5 days; stirring a couple of times each day.
Note: a whiteish crusty film was formed along the edge of the shot glass repeatedly each day. This was scraped with a chop stick and pressed back into the mixture each time it was stirred. Suspect one of the chemicals was “Vaporizing” and condensing on the side of the shot glass.
c. I attempted unsuccessfully to use a “Spaghetti Press” to make “Stick Powder” from the mixture when it was mostly dried. Mixing and testing it with a chop stick, I thought it was a little dry but would go through the Press screen.
Unfortunately – The texture and resistance was to great and the pressures generated literally forced the screw on screen cap partially off. I have to get out a vice and remove the Screen – hopefully not damaged beyond repair. The Spaghetti Press I attempted to use can be found on Amazon at: https://www.amazon.com/dp/B0CKRSL1R8...roduct_details
I am not going to give up on trying to make “Stick Powder” using this formula; but it will have to be wetter than what I tried.
d. I used the chop stick to retrieve the mixture and scrape it all into a stainless steel small bowl. I used a stone Pestal to crush all the mixture into a powder. Then used an old Kitchen strainer to screen the crushed mixture. Mesh was coarse, not fine. Same strainer that I use to scree corn cob media through when getting brass from a tumbler.
Picture of the Home Made No.7 Powder after grinding:
Attachment 322297
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Load Data for Experimental Test #1 - No7 Smokeless Powder
I loaded five rounds of .308 Winchester with the Experimental No.7 Powder this morning. The experimental batch I made up was sufficient for five rounds at 33 Grains, with a little left over; almost another case full. Initially the volume looked small, but when weighing it out I was able to get five for Testing when the Temps and Weather clears up.
Fortunately the information found on powder making in PRIMERS for Small Arms Cartridges by M. J. ALBERT and H. F. OELBERG, provided sufficient information to extrapolate a load for the .308 Winchester. The article provided some testing data they did back in the 1940’s with information on 8mm Mauser and 30-06 with the No.7 Powder, listing powder weight (in this experiment 33 grains), and Bullet Weights (150 grains) for their Testing. Comparing case capacity and pressure ratings of the three cartridges gives me some confidence for the 33 Grain No. 7 with Hornady 150 Grain FMJ Bullets in the Load Testing coming up.
Comparison of 8mm Mauser, 30-06, and .308 Winchester Cases:
CaseWater Capacity
Max Pressure PSI
8mm Mauser 63.1
56560
30-0668
58740
30856
60191
The powder load selected was 33 Grains. From a case volume perspective; this places the powder just at the base of the neck for the cases I am using.
Attachment 322300