Originally Posted by Mule Deer
Originally Posted by OldmanoftheSea
John,
Do you have a "feel" for the relative volume or "packing" of the three 4350s?

Just curious if the key might be on the "the amount of powder that will burn" as controlled by the available oxygen...


Both H4350 and A4350 are "short cut" powders, with similar-sized granules. IMR4350 granules are about the same diameter but much longer.

Thanks John.
I thought about phrasing my question around powder form factor later...
And that the ease of metering is a rough parallel to packing efficiency...

Originally Posted by 300_savage
As I understand it, the amount of molecular oxygen available in the cartridge case from air is negligible. The "oxygen" in smokeless powder is provided through an oxidizing agent, namely the nitro groups of the nitrocellulose which accept electrons from the carbon of the cellulose portion of the nitrocellulose. This is similar to molecular oxygen accepting electrons from the fuel in open air combustion of fuels. In black powder, the fuel is the charcoal (carbon) and the oxidizer is the potassium nitrate.

Thanks.
I found a NATO paper that discussed double base solid propellants (a 42%NC-52%NG mix having about 1,100 calories per gram)

NATO paper on solid propellants

Basically my takeaway was that the preheating zone of the powder breaks the bond between NO2//C&O allowing combustion to start.
Combustion goes in two phases NO2 and Secondly NO oxygenated...
No mention was made of ambient oxygen..

Interestingly though they found that copper and lead salts in addition to carbon black had a positive effect on the NO oxygenated portion of the flame.
This might provide some support for observations of a second shot being slightly faster than the proceeding fouler...

Sorry for the sidetrack....

-OMotS


"If memory serves fails me..."
Quote: ( unnamed) "been prtty deep in the cooler todaay "

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