2F vs 3F

[silly goose]

Guys, help me out. Ive had a moment to think about something, and I know darn well that can be dangerous, but here goes. The question between using 2f and 3f powder comes up often enough, and it is usually stated that when you use 3f, you use appx 10% less, and therefore get more shots per pound of powder. My thinking is that 3f would be a bit more dense, due to less air space, meaning that there would be less by volume than 2f in a pound. So going along those lines, wouldn't that even out the shots per pound argument, at least to some degree. Sorry, fellas, I don't have time right now to set up shop and do some experimenting, just thought this may have been done already. Thanks.

 

[Mike Brooks]

I never reduced the charge.

 

[lonehunter]

goose, Volume is volume!
If you have a five gallon bucket of sand, or a five gallon bucket of marbles, Its still five gallons.
I see what you are saying about the larger air space between the larger grains of powder, But I bet a nickle that the unused air space in a 100gr charge would not equal even close to 1gr.
The recomended drop in load from 2f to 3f is due to the 3f granuals are smaller so they burn a little faster creating higher pressure.
So a 100gr charge of 2f should be close to the same pressure as a 90gr charge of 3f.
Thats the way I understand it anyway. :wink:
But as Mr, Brooks stated, Some dont reduce the charge at all. I shoot a pretty stiff charge of 3f in my .50 but I choose 3f because I found the fouling to be a lot less than 2f and still retain the accuracy..

 

[DOUBLEDEUCE 1]

Brother, can you spare a marble? :youcrazy: :rotf:

 

[silly goose]

You are correct volume is volume, but we buy powder by the pound. If there is less air space in 3f, wont there be less volume in a pound of 3f than 2f?

 

[ApprenticeBuilder]

You are correct volume is volume, but we buy powder by the pound

Correct, but if you open a brand new can of 3F you will notice an amount of air space between the powder and the top of the can.

The built in volume compensation is designed right into the can, 1F comes in the same can as 4F and they weigh the same, pound for pound.

 

[Dan Hogue]

makes sense to me. Like Mike I don't change my loads either. Without getting too technical there has to be a conversion chart somewhere that tells how many grains of 3f per lb. oz or whatever, and the same for 2f.

 

[roundball]

You are correct volume is volume, but we buy powder by the pound. If there is less air space in 3f, wont there be less volume in a pound of 3f than 2f?

Although the difference is the number of volume measures thrown from a can of 2F vs. 3F would probably be very insignifcant, I agree with your assumption.

For example, if I have 7000 grains of 2f and am able to throw exactly 70 volume measures of 100grns 2F...I might only get 69.x measures of 3F volume from the 7000 grains of 3F.

Smaller granulation, less wasted air space, would pack more densely, more grains of weight per volume measure, fewer number of volume measures needed to use up the 7000 grains of 3F weight in the one pound can of 3F, etc

 

[roundball]

You are correct volume is volume, but we buy powder by the pound. If there is less air space in 3f, wont there be less volume in a pound of 3f than 2f?

I see what you are saying, There should be less powder (by volume) in a can of 3F, So where is the savings? :hmm:

IMO, the "less volume" would be a very small difference...and the "savings" would come from using less 3F vs. 2F to get the same pressure / velocity...ie: the 10% rule of thumb

 

[lonehunter]

So a 10% reduction in your charge you should get 76 measures from the same pound at 90gr per measure. Right? :hmm:
Should get appr. 7 more measures out of the same pound.

 

[roundball]

Yes, that's how I always figured it.
In the case of 100grn charges of 2F from the can of 7000 grains 2F, you'd get 70.
In the case of using 90grns 3F, you'd get 77 (or 76) shots from the 7000 grains of 3F.

And remember too, that none of these would work out precisely the same for everyone...too many variables in the consistency of physically pouring measured volume charges, etc...variations of the amount of granulation breakdown / 'fines' that get created within each can from handling...variations in the volume measures themselves from different manufacturers, etc

 

[gordy]

I would have to agree with Roundball, It would seem that some of the problem in understanding here may be due to the fact that powder is sold in weight measurement , but we load by volume .( unless you are trying to achieve max. duplication of each load ) For the most of us , a volume measure will be close enough. :hmm:

 

[Pacobillie]

If I may contribute to this discussion. Why do you assume that total air space in FFFG will be less than in FFG. Whilst there will be smaller spaces, there will also be more of them.

I never weighted similar volumes of BP in different granulations to find out which is heavier, but I recently did it with Pyrodex. And lo and behold, a set volume of Pyrodex P weighs more or less the same as the same volume of Pyrodex RS.

 

[George]

I never weighted similar volumes of BP in different granulations to find out which is heavier....

I have. Several months ago I got a new digits scale and did that exercise because of a discussion going on at the time.

I filled my antler measure with 3F Goex five times, measuring as accurately as I could, weighed them and got an average of 83.6 grains. Did the same with FFg Goex and got an average of 78.6 grains. Just as expected, increasing granule size reduced the weight of a set volume of powder, decreasing granule size increased the weight. The difference amounts to about 6%.

Spence

 

[illuveatar]

It seems to me that from a cost savings point of view that you'd only be saving a couple dollars per pound. Depending on your load size and the cost of blackpowder where you are that's a few cents per shot.

Wouldn't it be better to just use the type of powder that works best with your gun?

I'm new to the blackpowder world so let me clear something up here. If I have found my most accurate load to be 60 grains 2F can I assume that I would get equally accurate shots with ~54 grains of 3F ? all other things remaining the same ?

 

[Adui]

No..
FFF burns faster, which is why the pressure increase over ffg.

That said, changing to fffg powder will mean starting your load work up all over again. it would be worth it however, as you might find your gun likes fffg better..

 

[illuveatar]

Well that's what I thought, so now my question is why did the original poster mention just using 10% less 3F ? Is that a common misconception ?

I don't think that I would sacrifice accuracy to save a few bucks in powder. Though I don't shoot nearly as much as some other people around here. Even if one were to shoot a thousand round balls a year, that comes to around 10 pounds of powder and still only a savings of maybe $25. Obviously if your gun prefers 3F that's a bonus but I wouldn't switch purely to save the money.

 

[Bill Hall]

Here's something to think about. Which contains more air, a room full of bowling balls, or a room full of BB's? Exactly the same. Theoretcially, the airspace in 3f and 2f should be the same, or very close to it. Bill

 

[silly goose]

This has been a good discussion. I will say that I have no experience in comparing 2f and 3f, in my minimal experience, 2f has worked just fine. Someday when I get time, I wouldn't mind experimenting a bit. That being said, I do read lots of the information presented by others, and when the topic comes up, I have found repeatedly that the general rule is to reduce your charges by 10% when using 3f in lieu of 2f. That is where the 10% comes in. My motive for posting was because I doubted that there was a cost savings, which most folks use in their argument for 3f, due to starting out with less volume of 3f in the first place. Some of our more knowledgeable posters have answered my question, and I believe the answer is that yes, you should get another 6-7 shots per pound of 3f over 2f. Probably enough savings to buy yourself a cup of coffee. That being said, I do feel it is up to the individual to try both and let their gun tell them what they like to shoot. Good discussion fellas, thanks. I'm done thinking for a while now. :grin:

 

[roundball]

Just so we're clear on 'my' viewpoint about 3F, cost never enters into it...it's pennies...insignificant.
I always use 3F when/where ever I can simply and only because it gives faster ignition and burns cleaner, period.

I do have a .62cal smoothbore where a PRB deer hunting load gives an eyelash tighter group with 2F but even that's not enough to switch to 2F...but I go ahead and use 2F for that load because I have a case of 2F with little else to use it for, and the recoil from a full power load in that big bore is more of a push than a jolt like it would be if I was using a big charge of 3F.