What is Semi-smokeless powder?

tokguy

tokguy

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I finally got around to working on my Cape rifle. As far as I can tell it's a 9.3 X 57 R re-proofed to 360 express.
CombRside.jpg

Several helpful individuals have told me to mirror the loadings for 38-55. Cool I've got a 38-55. Should be easy, right?
The case full of FFg was really sedate.
Proofmarks.jpg

But I'm really leary of trying to interpret what Semi- smokeless powder might be. But it seems as though it falls short of nitro classification.
While I'd like to improve the power of this round; a trip to the hospital and wrecking a cool rifle seems like a bad way to spend the day.
My 38-55 doesn't entirely digest a hefty load of 4895. After a tube or two, some unburned grains migrate into the action. But semi-smokeless...?
Any thoughts as to what constitutes semi-smokeless?
 
I don't think semi-smokeless is highly technical term. It usually means a nitro (smokeless) BP replacement powder that mimics FFG black powder pressure AND volume qualities. There hasn't been any of this around for 60-80 years.

Cartridges of the World lists these 360 Express (2.25") loads:

190 gr lead bullet - 23.0 gr IMR4198 - 1650 fps (for 1800s BP-only rifles)
250 gr lead bullet - 26.0 gr IMR4198 - 1700 fps
 
There was a recent thread where the term "bulk smokeless" came up. It was an early smokeless and you filled the case just like with BP but you only required about 1/3 the actual weight. They are no longer made.
 
"Semi-smokeless" powder came out in the 1890's for people who wanted to re-load their ammo but weren't into bothering with weighing charges. They were also called "bulk" powders. You could load them bulk for bulk with black powder. They mostly disappeared early on except for DuPont Bulk Shotgun which was available into the 1960's (Cartridges of the World).

That's a beautiful gun. I'd be wary of using stiff smokeless powder loads. I'm going from memory but I think that the proof mark on the far right of the last photo (ELG with star & crown) is a Belgian black powder proof mark.
 
Goldenlakepete said:
"Semi-smokeless" powder came out in the 1890's for people who wanted to re-load their ammo but weren't into bothering with weighing charges. They were also called "bulk" powders. You could load them bulk for bulk with black powder. They mostly disappeared early on except for DuPont Bulk Shotgun which was available into the 1960's (Cartridges of the World).

That's a beautiful gun. I'd be wary of using stiff smokeless powder loads. I'm going from memory but I think that the proof mark on the far right of the last photo (ELG with star & crown) is a Belgian black powder proof mark.
Click to expand...

According to my reference material that's called a "provisional nitro proof" introduced in Belgium in 1897.
With other supporting information such as manufacturer's records, serial numbers etc. it can sometimes be used to authenticate "pre 1898 manufacture". Cannot be used for that dating by itself, and yes, it was used for bulk black powder replacement.
 
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