FFF powder in a .62 caliber smoothie?

[Banjoman]

My first flintlock smooth bore came with about a half pound of some kind of coarse 1f or reenactment powder. I used it up cause it was my first real black powder. Found out later that 2f and then 3f was better. I’d like to try 4f sometime.

 

[JeeeperBillMI]

I have a Rice .62/20 gauge smooth barrel and FF is the recommended powder load. However, I have several pounds of FFF on hand that I bought for a smaller caliber rifle that I no longer use. Can the smaller grain FFF powder be safely used in a .62 smoothie or will that create too much pressure?

I have been shooting a .62 cal in trade gun in competitions with a group regularly. Almost everyone I shoot with loads with 3F and primes with 4F. There are some at the competitions that still use 2F for loading but they are few. I personally use 3F in all of my muzzleloaders because it cleans up so well. I get very little fouling even at the end of a match and clean up is a breeze. My thought is that the 3F burns more completely making for less fouling. I have noticed it does burn a little hotter and I do back off in my 0.50 cal rifles but I leave my trade gun load at 60 grains for round ball and 70 grains for shot.

 

[wiscoaster]

2F makes thicker BP smoke, therefore works better to obscure the sight pictures of the AR shooters on the downwind benches.

 

[PathfinderNC]

Ok, so with all the props here for FFF, this begs the question: Why use FF?

For a simple reason that some guns do better with 2f than 3f.
I’m no scientist but I can see the difference.
It is what it is.

 

[waksupi]

I've always used 3FFF.

 

[Gordoncourtney]

I have a Rice .62/20 gauge smooth barrel and FF is the recommended powder load. However, I have several pounds of FFF on hand that I bought for a smaller caliber rifle that I no longer use. Can the smaller grain FFF powder be safely used in a .62 smoothie or will that create too much pressure?

Think it was on graeme Wright book. Adjust the powder measure until the chronograph shows the correct velocity , then the powder measure will be correct Ie say 1300 ft:sec. Of course you are stuck without a chronograph.

 

[LT Joe]

3F is all I shoot in all my guns. Have done so for years. Makes things a lot simpler when you only use one type of powder.

 

[Rob M.]

The reason for different granulations ... The finer powder builds more pressure on ignition ....thats the reason but it dont know how , why it would effect me BUT ....thats the reason .... 60 gr. of 3F will cause the round ball to go faster than 60 gr. of 2F ... Is it a safety thing or a " consistent accuracy thing ? Probably a bit of both .... I shoot only 60 gr. of powder in my 20 ga. N.W. gun so it doesnt bother me . Safety wise I'm fine . I know !d!0t$ that shoot 150 gr. in their trade guns but ...thats on them . Now accuracy wise ....doesnt bother me either as I am a minute of deer kind of guy . A precision rifle shooter is going to see the difference but not me . If all my shots are hitting the steel or are on the paper plate ....I'm good with that ....but some shooters , if that group opened up or the group moved up or down two inches ... they'll be having at fit !! My homemade BP ....even after granulating it , its a mix of 2F , 3F and 4 F .... I dont seperate it ....doesnt bother me any ....

 

[maillemaker]

I use 3F in everything, from revolvers to .50, .54, and .58 rifled guns, to my .69 smoothbore. 70 grains 3F Goex in my .69 smoothbores.

My understanding is that 70 grains of 1F and 70 grains of 3F (by weight, as grains is a measure of weight, not volume) contain the same amount of energy. Black powder is the same chemically no matter how you grind it up.

However, the smaller grain size means increased surface area exposed to combustion gasses, and as such the finer the granulation the faster the energy is produced.

So finer granulation will generate a faster and greater pressure spike.

Google's AI summarizes:

AI Overview

When comparing the pressure curve of 3F and 2F black powder, 3F powder will generally produce a quicker, higher peak pressure compared to 2F powder due to its finer grain size, resulting in faster burning and more rapid pressure development in a firearm chamber.
Key points to remember:

Grain size:
3F powder has significantly smaller grains than 2F powder, leading to a faster burn rate.

Pressure curve shape:
This faster burn translates to a steeper pressure curve for 3F powder, with a quicker rise to peak pressure and a faster decline.

Applications:
Due to its high pressure characteristics, 3F powder is often used in situations where quick ignition and high power are needed, like small caliber pistols, while 2F powder might be preferred for larger caliber firearms where a slightly slower burn is desired.

 

[maillemaker]

 

[Banjoman]

The reason for different granulations ... The finer powder builds more pressure on ignition ....thats the reason but it dont know how , why it would effect me BUT ....thats the reason .... 60 gr. of 3F will cause the round ball to go faster than 60 gr. of 2F ... Is it a safety thing or a " consistent accuracy thing ? Probably a bit of both .... I shoot only 60 gr. of powder in my 20 ga. N.W. gun so it doesnt bother me . Safety wise I'm fine . I know !d!0t$ that shoot 150 gr. in their trade guns but ...thats on them . Now accuracy wise ....doesnt bother me either as I am a minute of deer kind of guy . A precision rifle shooter is going to see the difference but not me . If all my shots are hitting the steel or are on the paper plate ....I'm good with that ....but some shooters , if that group opened up or the group moved up or down two inches ... they'll be having at fit !! My homemade BP ....even after granulating it , its a mix of 2F , 3F and 4 F .... I dont seperate it ....doesnt bother me any ....

Yep, me too.

 

[Britsmoothy]

View attachment 378050

So according to the chart 4f is a pussy cat

 

[Loyalist Dave]

Ok, so with all the props here for FFF, this begs the question: Why use FF?

...,
Because some fool spread fear.
...,
You said 2f is recommended, by who?

Well it was the manufacturers and importers, and probably dates back to the years leading up the the American Bicentennial, and people shooting grandad's original old rifle, without a proper check, and blowing the gun and themselves up.

The barrel manufacturer recommended FF. Did not give a reason but cited in an email the familiar rule of thumb that FFF is for < .50 cal and FF for larger calibers. Any idea where that rule of thumb came from?

NOPE but it's not just the barrel makers...,


Powder Information, Leman Guide

Powder information CVA

Powder Information, PEDERSOLI

Powder Information TRADITIONS sidelock manual

AH but NOW look at the TRADITIONS powder loading chart, and you see 3Fg and 2Fg listed for rifles much larger than .45 caliber...YET you will also see the pan powder that is suggested is only 4Fg.

SO we can follow what the lawyers have told the manufacturers to write in their manuals, and apparently in one case contradict from one page to another, OR we can follow the advice of fellows who actually put the stuff to use in modern made repros, and originals, and put wild game in the pot and on the table.

My personal experience AFTER messaging with @Britsmoothy is:

2Fg in a my trade gun = lots of smoke and noise but NO game
3Fg in both my flintlock trade gun AND my SxS Caplock 20 gauge = squirrels and pheasant and grouse in my game bag.

3Fg in my Flintlock .54 both main charge and prime of the pan (without consulting anybody) = several deer in the freezer.

LD

 

[Brokennock]

I generally prefer 3f, so do both my smoothbore flintlocks. Seems to shoot cleaner, just judging by the feel of reloads, and I can match or even improve on the performance of a 2f load using 3f.

Why do some still like 2f? Well for one thing, I do notice slightly less recoil with 2f when comparing loads that produce similar results. Also we often find that larger powder granulations produce better, more even, shot patterns. But this is at the cost of reduced energy on target.

 

[Onojutta]

First let me say that this is a great thread and I really appreciate all the replies. Now for some follow up...

My homemade BP ....even after granulating it , its a mix of 2F , 3F and 4 F .... I dont seperate it ....doesnt bother me any ....

That's a great point and we probably have a lot more consistent and precise granulations available today. In the old days, my guess is that powder granulation varied a lot more than it does today and we're probably on the verge of over thinking it. Speaking for myself anyway.

My understanding is that 70 grains of 1F and 70 grains of 3F (by weight, as grains is a measure of weight, not volume) contain the same amount of energy. Black powder is the same chemically no matter how you grind it up.

However, the smaller grain size means increased surface area exposed to combustion gasses, and as such the finer the granulation the faster the energy is produced.

So finer granulation will generate a faster and greater pressure spike.

Thinking about it like a soil, the finer particles will have less "pore" or empty space between them and therefore the same volume charge FFF will contain more powder mass than the same volume charge of FF. The increased density likely explains why we perceive more energy from the FFF even though it's all the same substance as you point out.

SO we can follow what the lawyers have told the manufacturers to write in their manuals, and apparently in one case contradict from one page to another, OR we can follow the advice of fellows who actually put the stuff to use in modern made repros, and originals, and put wild game in the pot and on the table.

Indeed! And that is why this is a great forum.

So I guess my last question on this is, practically speaking what would it take to over charge and damage a barrel? I remember reading on another post a while back that Jim Kibler initially had some concerns with the thinner barrel walls of his Fowler kit being subject to excessive pressure from tightly patched round balls if guys load up a fowler the same way they would a rifle. Loading up a smoothbore that was meant to be a shotgun the same way we might load a rifle is a bit of a different problem, but that aside, I do wonder how much FFF would truly be unsafe for normal loads...