European Powder Kernel Size

[MikeC]

I read somewhere that FF-Swiss is equivilant to Goex FFF. Is that correct? If that is true than I would assume FFF-Swiss is the same kernel size as goex FFFF.

 

[Mad Monk]

I can give you some idea of grain size differences by comparing the screen sizes of each.

GOEX, WANO and KIK

3Fg 20 mesh - 50 mesh
2Fg 16 mesh - 30 mesh
1Fg 12 mesh - 16 mesh

With Swiss.

3Fg 18 mesh - 32 mesh
2Fg 12 mesh - 24 mesh
1Fg 10 mesh - 14 mesh

1&1/2Fg 12 mesh - 18 mesh

The Swiss 1Fg is slightly larger than U.S. 1Fg.
The Swiss 1&1/2 Fg is very close to a U.S. 1Fg
The Swiss 2Fg is slightly larger than a U.S. 2Fg.
The Swiss 3Fg is larger in size compared to a U.S. 3Fg.

 

[MikeC]

Thanks for the reply. I didn't think that sounded right.

 

[wszumera]

What is the dimensions of the various meshes?

Clutch

 

[paulvallandigham]

The mesh size is as stated, but you have to understand that those numbers represent a number of holes in a square inch of screening. 32 mesh means there are 32 holes in a square inch of screening. Nw, what actual diameter of powder granule will pass through there is also a good question, and I suspect that is what you are really wanting to know.

 

[Mad Monk]

The Tyler Standard Sieve chart that I have gives the screen size openings in millimeters, not inches.

U.S. grain sizing screens.
(FFFg) 20 mesh to 50 mesh --- 0.84mm to 0.290mm
(FFg) 16 mesh to 30 mesh --- 1.0mm to 0.55mm
(Fg) 12 mesh to 16 mesh --- 1.41mm to 1.00mm

Swiss grain sizing screens
FFFFg 32 mesh to 60 mesh --- .226mm to 0.508mm
FFFg 18 mesh to 32 mesh --- .508mm to 0.870mm
FFg 12 mesh to 24 mesh --- .670mm to 1.36mm
1.5Fg 12 mesh to 18 mesh --- .900mm to 1.36mm
Fg 10 mesh to 14 mesh --- 1.20mm to 1.60mm

The exact size of the openings will depend on how much one is willing to pay for stainless steel screens.
When you start going below 20 mesh screens little differences in wire diameter make differences in what will pass and what will not.

In dealing with the screening of black powder you have grain shape to deal with. Highly irregular shape.


The American grain sizes were introduced in 1836 as a means of standardizing grain sizing within the industry. Any real degree of standardization did not come about until late in the 19th century.
Originally there was no overlapping as we see now in the screen sizes.
The original screen sizing gave what might be called a halving effect. That is to say that the average diameter of 2F was half the average diameter of 1F. 3F was half the size of 2F.

Little differences in grain sizing do not make the difference that differences in density and burn rates will in a gun.