Sciencemadness Discussion Board

Composition B propellant

Daffodile - 28-1-2020 at 22:58

Hey all, just curious if anyones ever heard of any comp B propellant before. Apparently the 81mm mortar propellant at work is listed as that, but I feel like it might actually be cordite or something else.

Comp B just seems like it would provide a too violent detonation to be used as a propellant (despite the short mortar barrel) and that the extreme oxygen deficit would hinder the mortar's performance. Any thoughts? The exhausted cloud looks white-grey, with less sooty residue than one might expect from something so OB negative, but it also gets exhausted very rapidly and the colour could be deceptive.

Fulmen - 29-1-2020 at 01:12

Comp B is not a propellant, it's a melt-cast explosive. It might be used as the main filler in explosive shells, but would be utterly useless as a propellant.

Microtek - 29-1-2020 at 02:23

I worked in an 81-mm mortar section when I was in the army. It used ordinary smokeless powder (NC/NG blend) around the base of the shell, although it may have been a different system to the one you are using. RDX, HMX and other explosives are used in some propellants (mostly for rockets, AFAIK), but it is generally undesirable to have components that melt before decomposition in a propellant.

[Edited on 29-1-2020 by Microtek]

B(a)P - 29-1-2020 at 03:24

My records are for older rounds (I can't access the most recent info because of its classification), but to my knowledge they have always used nitrocellulose based propellants.

[Edited on 29-1-2020 by B(a)P]

caterpillar - 29-1-2020 at 16:06

Quote: Originally posted by B(a)P  
My records are for older rounds (I can't access the most recent info because of its classification), but to my knowledge they have always used nitrocellulose based propellants.

[Edited on 29-1-2020 by B(a)P]


Some gun propellants content RDX. I was surprised when I found such info. However, there are problems with such formulations- hi temp of burning RDX particles.

Comp B

MadHatter - 29-1-2020 at 20:56

As pointed out in this thread, COMP B is a high
explosive(bursting charge) used by the military in
everything from grenades to artillery shells and
more. It's based on cyclotol, which, IIRC, is 60%
RDX and 40% TNT. The main difference is that the
proportions for COMP B are slightly lower due to
the paraffin in the mixture.

HEs have been mixed with other compounds to
make rocket fuel. In some cases used as mono-
propellants. COMP B doesn't fit in this category.