BP – Smokeless - Air Space

SIGP2101

SIGP2101

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BP – Smokeless - Air Space



Can someone clarify this for me once and for all.

BP in BP cartridge = no air space TRUE/FALSE

BP in SMOKELESS cartridge = no air space TRUE/FALSE

SMOKELESS in BP cartridge = no air space TRUE/FALSE

SMOKELESS in SMOKELESS cartridge = no air space TRUE/FALSE


THANKS
 
BP-BP. Usually compressed.
BP -Smokeless. In something like a .38, it would likely be compressed.
Smokeless-BP. Usually airspace, because a smaller volume of smokeless is required. In some cases this can lead to ignition/consistancy problems.
Smokeless-smokeless. Sometimes compressed, sometimes airspace.
It will really depend on the specific cartridge, though.
 
SIGP2102 Black Powder Has to be compressed in any Cartridge NO AIR SPACES WITH BLACK POWDER AT ALL.
Smokeless in any Cartridge can have air spaces, but if you have a huge case you are wise to watch what powder you are using because some are position sensative.
This brings in using fillers to keep the powder against the primer. This one can get pretty contraversial depending on whom you are talking to and what you want to use for a filler.
Ken
 
Thanks guys,

That clarifies some doubts about air space. Now I need more reading about why no air in BP. Any suggestions?
 
It has been observed that if a significant gap is left between the powder charge and projectile in a ML barrel, even a modern steel barrel can be bulged or burst. Apparently there is a pressure hammer or shockwave effect. I do not know if this could be duplicated in a cartridge. The gap would be much smaller than in a ML situation. Nevertheless, it is generally thought that a BP cartridge functions best if the charge is under a bit of compression.
 
Yes that can be duplicated in a cartridge that is why you have to compress your powder with a compression die after putting you wad on top. Then you make sure that your bullet is seated tight to the wad or you can get the same pressure spike and that could be the end of all your shooting.
Ken.
 
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