DIY Smokeless Powder - No. 7 Smokeless Powder Manufacturing

[MUSTANG]

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.

[MUSTANG]

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:

[MUSTANG]

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:

Case

Water Capacity

Max Pressure PSI

8mm Mauser

63.1

56560

30-06

68

58740

308

56

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.

[MUSTANG]

The various characteristics of the Rifle and conditions for the No.7 Home Made Smokeless Powder Experiment #1 appears below. I used commercial Large Pistol Primers; Gold Medal Large Pistol Magnum Match Primers #155M. Might have been better to have used commercial Large Rifle Primers; but given difficulties in purchasing them I have decided to save those. I also am not using any of my “Remanufactured” primers in this Testing for now to Limit the variables in exploring making my own Smokeless Powder.

Rifle: Remington 700 ADL Varmint .308
Barrel Twist: 1 in 12
Jacketed Bullet: Hornady 150 Grain .308 FMJ.
Ballistic Coefficient:
Brinnel Hardness: N/A
Bullet sized: .308
Alloy: N/A
Bullet Lube: N/A
Gas Check: N/A
Powder: No.7 Home Made Smokeless Powder Experiment #1
Primer: Gold Medal Large Pistol Magnum Match Primers #155M
Case: Mixed commercial Brass
OAL: 2.710 inches
Distance: 100 Yards.


We will see how this performs, hopefully next week weather permitting. I am cautiously optimistic, but know that I deviated in some of the production, so “We Will See”.

[HWooldridge]

Was this an early DuPont powder or something the military developed?

[MUSTANG]

Was this an early DuPont powder or something the military developed?

Developed by "Experimenters" and published during World War II because they could not get commercial Ammunition - nor could they get Powder for Shooting and Hunting. Note the use of "Charcoal". There is a recipe for making and using Hydrocellulose instead of Charcoal; but I am focusing on what I have on hand vs expanding into adding muriatic acid and another item that has to be "Remanufactured" before I can make the powder as part of my current experimentation.


One of the reasons I selected the No7 Formula was because of the Table in the reference that indicated a drop of only one inch at 100 yards compared to IMR 4320 Powder (in 1944) with a 2 & 1/2 drop based on same sight holdings for all Test Loads.



Click on the Table to enlarge for viewing.

[Nobade]

Fascinating! A more refined amonpulver. Definitely want to follow this!

[ofitg]

Interesting stuff! Will you be chronographing your test loads?

[justindad]

How precisely do you need to control kernel size & shape?

[jdsingleshot]

Watching this!

[MUSTANG]

Interesting stuff! Will you be chronographing your test loads?

It is my intention to Chronograph when I test. One goal if successful is to set the stage to compare the performance against my current reduced BLC-2 (30 Grain) loads I am using with dacron filler and RCBS 200 Sil.

My thoughts are based on the comparison table contained in the original 1944 paper, the powder may provide the same opportunity. My initial tests will be with Jacketed 150 Grain Hornady FMJ so if velocity is established in the 2000 fps to 2750 fps I can identify it as a highly energetic powder - and work towards reduced for Cast Boolits. If performance falls into the 1700 to 2000 fps; I can simply start working with cast and see how it progresses.

My current testing regimen is based upon the powder behaving similar to IMR 4320; in the 1944 paper the closest "Drop" comparison below sighting point was IMR4320. For current powder burn rate comparisons between a variety of powders - see the extracted burn rate table below. Note that todays IMR-4320 is listed with a Bon Rate on par with Varget.


Click on table to enlarge

[MUSTANG]

How precisely do you need to control kernel size & shape?

Unknown.

Doing some translation between the 1944 paper where they speak to a 12x12 hole screen size per 1 inch, I used a hand held kitchen strainer for my first effort. In their write up they kept/used all powder that spilled through; and reground & prescreened the particles that did not, adding them to the previous powder.

An area to explore after I verify that the powder I produced will go Bang; drive a 150 Grain FMJ, and do so at sufficient velocity to be useful. The continual increases in Powder prices is a driving reason why I am experimenting. I have a good supply of Rifle Powders; and an additional good supply of WC-860/WC-870/WC-872 powders that I use in 50 BMG and in duplex loads for cast; but having alternatives in out years is important to me if needed.

[pworley1]

Very interesting.

[GhostHawk]

With the Ammonium Nitrate I assume that powder will be corrosive?

[elmacgyver0]

I have not yet tried to make primers, although I am close, I have all the fixings, but have not had the ambition to actually do it, perhaps this weekend.
Good luck with your powder experiments.
I need to start catching up.

[MUSTANG]

With the Ammonium Nitrate I assume that powder will be corrosive?

From the Paper:

No. 7 is a smokeless powder, flashless under working load, hygroscopic; and retains all of the cool burning, low pressure merits of all Ammonium Nitrate powders, as well as the one hygroscopic disadvantage.

[dverna]

Please forgive my ignorance

As a precursor, I will never remanufacture primers for two reasons. I am uncomfortable dealing with explosive mixtures and I am blessed to be able to afford commercial primers.

So, my concern is, how safe is this formulation wrt to making it in large quantities? Can it be produced indoors?

I am looking forward to your range report!

[MUSTANG]

One reason why after following the mixing instructions I let it dry for 5 days was because the guidance for the three Home Made powders in the manual call to "Cook the Powder" over a low flame - and to have water available to put out a fire should it catch fire. Given the -35 temps; I did not want to cook it over the Kitchen Range. The materials ARE NOT EXPLOSIVE for this mixture. They burn rapidly and create large volumes of gas to propel the bullet.

The reference particularly warns against the use of Chlorates for powder production. From the manual:

THE USE OF CHLORATES, AND PARTICULARILY POTASSIUM CHLORATE, IN PROPELLANT POWDERS IS SPECIFICALLY BAD. Chlorates have been tried, in every combination, particularly with sugar, and are always to be regarded as DETONATING EXPLOSIVES. Chlorate Ex- plosives are generally known for their brisance. They are known for their sensi- tiveness to friction. Chlorates are essential and indispensable in primers: but have no place in propellants whatever.

If my five test rounds perform poorly; I'll look into "Cooking" the mixture as it is possible I may be missing a factor affecting the chemical conversion for the Powder manufacturing. I am not a chemist; so anyone who is and has insight please provide comment.

[ofitg]

One reason why after following the mixing instructions I let it dry for 5 days was because the guidance for the three Home Made powders in the manual call to "Cook the Powder" over a low flame - and to have water available to put out a fire should it catch fire. Given the -35 temps; I did not want to cook it over the Kitchen Range. The materials ARE NOT EXPLOSIVE for this mixture. They burn rapidly and create large volumes of gas to propel the bullet.

The reference particularly warns against the use of Chlorates for powder production. From the manual:

THE USE OF CHLORATES, AND PARTICULARILY POTASSIUM CHLORATE, IN PROPELLANT POWDERS IS SPECIFICALLY BAD. Chlorates have been tried, in every combination, particularly with sugar, and are always to be regarded as DETONATING EXPLOSIVES. Chlorate Ex- plosives are generally known for their brisance. They are known for their sensi- tiveness to friction. Chlorates are essential and indispensable in primers: but have no place in propellants whatever.

If my five test rounds perform poorly; I'll look into "Cooking" the mixture as it is possible I may be missing a factor affecting the chemical conversion for the Powder manufacturing. I am not a chemist; so anyone who is and has insight please provide comment.

Are you familiar with this document, TM 31-210 ? Do you think it is legitimate?

https://www.militarynewbie.com/wp-co...f-the-Army.pdf

EDIT - looking around on the Internet, it seems that TM 31-210 is the "real deal", published by the U.S. Army in 1969

[MUSTANG]

Yep - Real deal. Portions of the TM appear in the "Anarchists Cook Book" published in 1971. In the past; I had been told that the precursor to the TM 31-210 was made up by the Intelligence Community and provided to sponsored groups in foreign countries where they could not smuggle conventional arms and munitions into.

TM 31-210 was published 25 years after the 1944 reference I used for No.7 powder. It also differs in that it's focus on explosive mixtures; whereas the No.7 smokeless powder (and other smokeless powder formulas) are gas generating mixtures vs explosive mixtures. Some of the explosive chemicals and mixtures in the TM can be found in the manufacturing of primers - albeit much much smaller units made up for primer application.

In my experience; much discomfort and pain can be avoided by preparing in advance instead of waiting for crisis to arise. This thread will focus is on Chemical Gas Generating mixtures used in making smokeless Powder, as an alternative in the future if commercial powders are unavailable and stocks of commercial powders are unavailable/too costly, or so limited the alternatives are required - just as was occurring in the 1944 World War II period where all resources were focused on the National War effort and not available to the General Population.