Double base vs. Single base powders

[Linus]

What are the advantages/disadvantages of double vs. single base powders? Also, what are their recommended uses?

[jwest]

Linus,

From wikipedia: (http://uiboss.com/wiki/Internal_ball...se_propellants)

edit] Double-base propellants
Main articles: Ballistite, Cordite, and Smokeless powder

To further increase the energy of smokeless powder, nitroglycerin can be added in amounts up to 50%. These powders are called "double-base powders", since both their main components actively produce energy, and they have similar basic physical properties to single-base powders. The nitrocellulose serves to desensitize the highly unstable nitroglycerin, preventing it from detonating as a high explosive, and the nitroglycerin gelatinises the nitrocellulose and greatly increases the energy density of the resulting powder. Double-base powders burn faster than single-base powders of the same shape, though not as cleanly, and in general the higher the nitroglycerin content of a powder, the faster the burn rate.

In artillery, Ballistite or Cordite has been used in the form of rods, tubes, slotted-tube, perforated-cylinder or multi-tubular; the geometry being chosen to provide the required burning characteristics. (Round balls or rods, for example, are "degressive-burning" because their production of gas decreases with their surface area as the balls or rods burn smaller; thin flakes are "neutral-burning," since they burn on their flat surfaces until the flake is completely consumed. The longitudally-perforated or multi-perforated cylinders used in large, long-barreled rifles or cannon are "progressive-burning;" the burning surface increases as the inside diameter of the holes enlarges, giving sustained burning and a long, continuous push on the projectile to produce higher velocity without increasing the peak pressure unduly. Progressive-burning powder compensates somewhat for the pressure drop as the projectile moves down the bore and increases the volume behind it.)

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I'm definitely not an expert on this - but I found that with a search on cuil.com - google.com has been a little unstable this evening.

HTH.
Regards,
jwest

[xrMike]

I remember Randall saying in a recent thread that double-base powders are more temperature sensitive than single base.

[ar15barrels]

Most ball powders are double based.
Many stick powders are single based.

[Linus]

Thanks guys,
how about their recommended uses though? Or are there no significant advantages in using a specific type for specific loads?