Powder sifting screen?

[Old Ironsights]

I'm told that my previous post might be confusing (me? confusing? who-da thunk it?), so:

What I'm doing with my screen setup is exactly as queried above - sifting 4F from 3F.

According to the industry, commercial 3F granulation is a range from .0330in - .0114in

So, I started with "3F" that contained granules ranging from larger than .021 (30 mesh - what Cal-graf calls their 3F) down to micron fines.

Thus I chose a "Hold" screen with a .015 Pass - ( 40 mesh.)

What passed my screen as "4F" runs from .0149 to Micron size.

Commercial 4F is considered to be any grain size from .0165in - .0059in.

I intend to re-sift my "4F" with a 60mesh .009 Hold to seperate the .0089 and smaller from the .0149 - .0091, essentially giving me "pure" 4F (which I intend to use in cartridges, & my ROA) and 7F or "Nul B" equivelent Flash powder, which I will use as dry-weather Prime.

Make sense?

 

[rabbit03]

Thank you for the web site address and the information. I will be referring back to your data if I can get this off the ground.

I have heard that it might not make that much of a difference in the accuracy but I would like to give it a try and see for myself. So again, thank you for the info, I appreciate it

rabbit03

 

[Old Ironsights]

Actually, while it doesn't make so much difference in "accuracy" it makes a BIG difference in Standard Deviations between loads.

Watch what happens some time during a range session when you empty one can of powder and start using another. Each Lot/Can will have a different "mix" and make your gun shoot to a different POI.

Sifting removes the "mixed granulation/burn-rate" variable from the equation.

Sifted powder also burns cleaner.

Swiss 3F tends to be mostly .021" or larger. It is around 80% consistant granulation. Everyone raves about how consistantly itshoots and how cleanly it shoots.

When I sifted cheap Chinese powder to match, the Standard Deviations and cleanliness quickly approached Swiss. Velocity was a little less, but not greatly so.

So, there IS a benefit to it.

 

[renovato]

That's what I had heard and exactly why I was wanting to do it too. Well, that and to get 4F for priming. The weather is very dry here most of the year, so I don't need to worry about humidity. Also, 3F tends to jam in my tiny priming flask.

 

[CrackStock]

I suspect that you will also get a higher concentration of graphite in the finer grains which might have an effect on your priming powder. It will be interesting to hear of your results.

CS

 

[Old Ironsights]

I suspect that you will also get a higher concentration of graphite in the finer grains which might have an effect on your priming powder. It will be interesting to hear of your results.

CS

My guess is it will have less effect on Prime (ignition) than it does on the bore (fouling).

Less Fines = Less Fouling.

 

[renovato]

I wasn't able to get out this week. I won't be able to get my car into the shop till tuesday, so it looks like next week before I can try it out.