DIY Smokeless Powder - A4 Smokeless Powder Manufacturing

[RyanJames170]

Very interesting!

I have to ask will this powder be corrosive though?

[Kosh75287]

Very interesting! I have to ask will this powder be corrosive, though?

I'D bet on it NOT being corrosive, or certainly not being AS corrosive as black powder. If memory serves, smokeless powders burn at a far higher temperature than black powder. The difference in burning temperature is that most/all of the potentially corrosive components will be consumed or converted to non/less corrosive products when smokeless powder is touched off. At the somewhat lower temperature of combustion for black powder, not all corrosive ingredients/products are consumed.

The corrosive characteristics of early military ammunition was from their primers being powered by highly energetic metalloid-mineral acid compounds (fulminate of mercury was probably the most common). Post WWII, these compounds were eventually replaced by the far less corrosive and much more manufacturer-friendly lead-aromatic acid compounds, like lead styphnate, and lead picrate.
If a mole of fulminic acid is added to a liter of pure water and thoroughly mixed, the solution has a pH of ~3.46, which is roughly 5 times more acidic than common household white vinegar (ALSO, a roughly 1mole/liter solution). If a mole of styphnic acid is mixed into a liter of pure water, the pH is ~10.5, which is so ALKALINE that it will not attack metals of the type(s) from which firearms are made. Weird, huh?

[MUSTANG]

Finished producing the A4 (Rev-1) Powder. Replacing the Hydrocellulose with Charcoal was listed as an option for the A4 powder in the 1944 Paper entitled - Primers for Small Arms Cartridges by Albert and Oelberg. This Rev1 Test lot production amount was scaled to produce enough powder to load 5 rounds, with each round having 32 Grains. Batch size produced was:

Ammonium Nitrate NH4NO3 70.1 Grains
Potassium Nitrate KNO3 38.4 Grains
Lead Nitrate Pb(NO3)2 38.4 Grains
Charcoal 23.1 Grains

Note: Per the original reference, the amount (by weight) of Charcoal is less than the A4 - Rev0 formula. Compare with the Hydrocellulose weight of 30.9 Grains in Post #19 above.

This batch was dehydrated for about 22 hours total at 130 degrees Fahrenheit in the Dehydrator. This A4 - Rev1 powder was NOT cooked on a stove, rather its was thoroughly mixed in well water (about 15 mili-liters) then placed into the dehydrator. The mixture was a dark black color, when dried it remained a dark black color.

The A4-Rev1 Powder was screened to fall through a 20 Mesh Screen; and all powder falling through that screen was mixed with about equal numbers of large and small kernels in each of the 5 rounds loaded into .308 cases with RCBS 200 Sil cast Boolits. Rounds were loaded soon after screening to preclude the powders picking up moisture from the air.

These 5 Rounds will be compared with the A4 Rev-0 batch to compare velocity and performance. Will be interesting to see any differences in performance between the Hydrocellulose and the Charcoal. Hope to get to the Range in next couple of days to test fore the Rev-0 and Rev-1 Powders.

[MUSTANG]

I was able to get to free a couple of hours this afternoon to spend at the Range. Tested the 5 rounds loaded with A4 Rev-0 Powder (Contains Hydrocellulose). The rounds were fired in a Remington 700 in .308 Winchester with a 26 inch barrel at a range of 100 yards. Temp was 72 degrees.

Group size for the five rounds was 8 inches. There is one round significantly outside the main group, if this shot hole is discounted – the 4 round group is 3 ¼ inches. I have no explanation for the “Flyer”. The Target group appears below:



Velocities in feet per second for the five round were:
1094
1018
1063
1100
1075

Average for the five rounds was 1070 fps.

[MUSTANG]

I tested the 5 rounds loaded with A4 Rev-1 Powder (Contains Charcoal instead of Hydrocellulose). The rounds were fired in a Remington 700 in .308 Winchester with a 26 inch barrel at a range of 100 yards. Temp was 72 degrees.

Group size for the five rounds was 9 1/2 inches. There is one round significantly outside the main group, if this shot hole is discounted – the 4 round group is 3 inches. The low velocity of one round is attributed to the “Flyer”, way below the other 4 rounds. The Target group appears below:



Velocities in feet per second for the five round were:
989
1351
1349
1337
1377

Average for the five rounds was 1290 fps.
Average velocity discounting the low velocity flyer was: 1353 fps.

[MUSTANG]

Making a reliable assessment of the two powders based on 5 rounds each could be problematic; but I believe we are getting some indicators. It appears that Charcoal (A4-Rev1) as a replacement for Hydrocellulose provides a higher velocity. This was surprising to me as the “alternative” listed in the original paper seems to provide what I see as a more desirable powder. For some; production of Charcoal can be a bit time consuming and/or problematic. For me, I take my charcoal from the ashes in the wood stove each morning throughout winter and make a fine powder of it using an electric coffee grinder.

I have no explanation for the single round of the A4 – Rev1 powder that was more than 300 fps below the average of the other four rounds. It does seem possible that the A4 – Rev1 may be producing a more narrow velocity spread than the A4 – Rev0 powder. Additional testing may or may not prove this postulation correct. There are some other mixture alternatives in the A4 powder that I will test in the next couple of weeks. Once those tests are completed; it should shed some light on what other testing may be beneficial.

[perotter]

Thank you for the report.

[Sandro_ventania]

Good job!

[2TM101]

This Rev1 Test lot production amount was scaled to produce enough powder to load 5 rounds, with each round having 32 Grains. Batch size produced was:

Ammonium Nitrate NH4NO3 70.1 Grains
Potassium Nitrate KNO3 38.4 Grains
Lead Nitrate Pb(NO3)2 38.4 Grains
Charcoal 23.1 Grains

What current smokeless powder would this be considered an equivalent to (for load purposes)?
Between the Ammonium Nitrate and the Charcoal, it sounds like this should be corrosive AND smoky?