How to lube old ammo?

bearhunter said:
Look it up. There have been several articles written about it.
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I actually believe you! Maybe my alzheimer's is playing up again!



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bearhunter said:
If you look at Ganderite's posts on this subject, it's not so much the kernels breaking down as it is the "graphite" coating on the kernels, which controls burn rate, being rubbed off during vibration.

It takes a lot of vibration to rub this stuff off, but it can be a serious issue.
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The graphite doesn’t control the burn rate.
 
Tokay444 said:
Graphite is not added to smokeless powder to control burn rate, and no one is removing it.
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It is, and it's one of the things stopping the kernels from sticking together, as well as other things. When powder is vibrated, by multiple methods, the kernels rub against each other too much the coating is rubbed away. When extreme conditions multiply this effect, burn rates are altered.
 
bearhunter said:
It is, and it's one of the things stopping the kernels from sticking together, as well as other things. When powder is vibrated, by multiple methods, the kernels rub against each other too much the coating is rubbed away. When extreme conditions multiply this effect, burn rates are altered.
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Graphite is used to keep kernels from sticking, strictly for metering purposes.
I challenge you to prove the rest of that BS.
 
For my friend Bearhunter.



This is what Science Direct research on nitrocellulose based smokeless powder production says -

​


Does using graphite coating on smokeless powder change the burn rate?

Yes, adding graphite to smokeless gunpowder changes the burn rate; specifically, the graphite coating in standard smokeless powder production helps moderate and control the burn rate.


Graphite is used as a standard additive in the manufacturing process of modern smokeless powders for several key reasons in order of importance:

  • Burn Rate Modification: Graphite acts as a burn rate deterrent or moderant, especially in the surface layers of the powder granules. The coating helps to seal the grains, ensuring a more consistent and controlled burn. This contributes to the powder's designed pressure curve when ignited within the confined space of a firearm barrel.
  • Safety and Handling: The added advantage of the use of the graphite coating is to reduce static electricity buildup, which prevents accidental ignition during manufacturing, transport, and loading processes.
  • Improved Flow: Graphite also can act as a lubricant, allowing the powder granules to flow smoothly and evenly through loading machines and powder measures.
While standard graphite coating mostly is used to moderate the burn rate, some advanced experimental propellants incorporate graphite fibers within the propellant matrix to enhance the burning rate, but this is a specific, specialized application not relevant to typical commercial smokeless powder.


Source - https://www.sciencedirect.com/science/article/pii/S2405844024173136

https://www.cell.com/action/showPdf?pii=S2405-8440(24)17313-6
 
No problem, but he and others may not have realized graphite's role as it is also true it is not used by all manufactures of small arms powder as some faster burning or single base powders do not either want that delayed burn rate or find it helpful. It is more a deterrent in slower burning powders but any powders formulated with it have a certain burning rate formula need and if it is removed that burn rate will be altered.

Less and less newer powders are also using it as a deterrent as they have moved onto other burn rate modifiers as graphite coated powders tend to burn a little dirtier and leave more residue in the bores of firearms.

This is other information I gleaned from my research -


Graphite is used in small arms powders primarily as a surface lubricant and an anti-static agent (glazing), which incidentally makes it function as a surface moderant (burning rate deterrent) by sealing the propellant grains and slowing initial ignition. It is not considered a primary temperature deterrent in the chemical sense of reducing the overall flame temperature of the reaction, just the actual rate of combustion and speed of propellant gas volume production.

Burning Rate Moderant: The graphite coating seals the surface of the propellant grains, slowing down the initial rate at which the surface ignites and burns. This contributes to a more controlled and consistent burn, which is a very desirable ballistic property. It is often applied in an aqueous slurry with other chemical deterrents (like dibutyl phthalate or centralite) during the manufacturing process to ensure an even coating that modifies the burn rate profile.

Not a Chemical Flame Temperature Deterrent

Graphite itself is a form of carbon, a fuel. It does not act as a chemical agent to lower the peak combustion temperature or heat of explosion of the propellant mixture in the way that specific chemical additives (e.g., nitroguanidine in triple-base propellants) do.

In summary, while graphite contributes to helpful moderating of the burning rate by physically coating the propellant surface, and slowing down the rate of combustion, its main roles in newer propellants are static dissipation and lubrication. Temperature deterrence in propellants is now achieved through different chemical formulations or additives built into the propellant powder.
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bearhunter said:
Thanx Mkernl, you beat me to it.
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A surface coating applied to smokeless powder to retard the initial burning rate, gas generation, and flame temperature is called a deterrent or surface moderant. These coatings slow down the initial burn to control the pressure in the firearm barrel, creating a more consistent and higher velocity for the projectile. Examples of deterrents include graphite, dinitrotoluene (DNT) or a defined linear polyester.

Smokeless powder that has neither a deterrent coating nor a graphite glaze is known as a base grain powder.



Function of the coating

  • Retards initial burn: The coating slows the initial combustion rate of the powder grains.
  • Manages gas generation: It also retards the initial rate of gas generation.
  • Controls flame temperature: The coating helps to manage the initial flame temperature, as well.

How it works

  • Initial effect: When the powder is ignited, the surface with the deterrent burns first, but at a slower rate.
  • Progressive burn: As the powder burns, the coating penetrates the grain more deeply, so the successively exposed surfaces contain less deterrent. This causes the combustion to proceed with increasing speed as the powder burns, which helps to maintain a more constant pressure on the projectile.

Examples of deterrents


  • Graphite: A common coating and glazing agent added to many powders, most importantly used for static control and protection.
  • Dinitrotoluene (DNT): A common deterrent that can be applied by heating the powder grains with a solution of DNT in a solvent like benzene.
  • Defined linear polyester: A more modern class of deterrent that acts as a plasticizer, diffuses into the powder, and is less likely to migrate at lower temperatures.

Other uses of Graphite coatings


Graphite's exceptional resistance to high temperatures means that it shows up in rocket and missile nozzle construction and coating, where it must withstand intense heat while maintaining structural integrity (a graphite specialty). And graphite is also useful in this re-entry process of rockets as well. In fact, you will find graphite serving critical roles in thermal protection systems (TPS) and re-entry vehicle heat shields. These applications require materials that can absorb and dissipate enormous amounts of heat without degrading or losing their protective properties. Graphite's thermal stability ensures that missiles, spacecraft and re-entry vehicles can survive the intense heating experienced during high speed atmospheric entry.


National Academies of Sciences, Engineering, and Medicine. 1998. Black and Smokeless Powders: Technologies for Finding Bombs and the Bomb Makers. Washington, DC: The National Academies Press. https://doi.org/10.17226/4029.
 
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