2F to 3F Powder Conversion

[Jefferson58]

Hi Folks:

I expect this question has been answered a 1000 times, but I can't seem to find anything that really gives a clear description:

Is there a good method for determining a comparable quantity of 3F powder to 2F powder? What I am looking for is basically a good rule of thumb for switching powder without drastically increasing pressure. If, for instance, I use 60 grains of 2F in a load and want to shoot 3F instead, is there a certain percentage of 3F to use versus the 2F amount?

Thanks for the help.

Jeff

[roundball]

Rule of thumb is to reduce 2F load data by 10-15% to keep pressures in the same ball park...I prefer 3F and use it in .40/.45/.50/.54/.58/.62cals because its always been faster, cleaner, and as accurate or more accurate than 2F for me...both rifles and smoothbores...ie: I just finished sighting in a new .58cal with 100grns Goex 2F deer load, then tried 90grns 3F and will stay with the 3F.

[northmn]

My Lyman BP Handbook lists pressure in a 54 in comparison.  120 grains 2f gives 1667 and 80 grains of 3f gives 1629.  Pressure is respectively 8100 LUP for the 2f and 8400 LUP for the 3f.  You are talking here about a reduction of 25%.  They list another example where equal velocities with 140 vs 100 has an increas of the 3f of 3200 LUP.  A 45 had comparative data at 8300 lUP for 70grains of 2F and 8710 for 3f at comparable velocities.  Interestingly the pressures with 2f went higher than 3f with charges over 80 grains of 2f.  2008 fps for 2f at 15100
and 13680 for 70 grains of 3f at 1994.  My guess is that 2f had to push a significanly heavier mass at a certain point.  Unless you have very sophisticated pressure equipment it would be hard to really get a picture.  The old rule of thumb used to be 3f up to 45 and 2f 50 up with a 50 being kind of an either or.  Daryl likes 65 grains of 2f in his 40, I believe.  It is possible looking at the 45 data he may be getting higher pressure than with 3f??   When I chronographed my 54 flinter I got very similar velocity figures to Lymans.  Use about 90 grains of 3f for a hunting load.  It has plenty of power for deer, shoots good and seems "quick".  Mostly it is a matter of keeping loads reasonable and seeing which works best.  Lyman felt that the pressures for 3f were higher but were not significant.  Other options are to use Swiss instead of GOEX etc.
DP

[Colonial Riflesmith]

Hi Jeff, I seems these guys know what they are taking about when it comes to heavyer loads and pressures. One thing I've noticed is that shooters on this site seem to like heavyer loads than I'm acustom too. I'm learning a lot from just reading their posts.

[Acer Saccharum]

Don't go by what Daryl burns....unless you like a sore shoulder... he likes big bores with lots of powder.... uses about 25 lb a year.

[Roger Fisher]

Don't go by what Daryl burns....unless you like a sore shoulder... he likes big bores with lots of powder.... uses about 25 lb a year.

Is that all?

[roundball]

Don't go by what Daryl burns....unless you like a sore shoulder... he likes big bores with lots of powder.... uses about 25 lb a year.

And only makes 25 shots...

[northmn]

Daryl likes heavier loads but not neccessarily in relationship to the ballweight powder weight proportion.  Roundball is exaggerating slightly, I am sure Daryl may get at least 100 shots out of his 25 pounds of powder.

DP

[Don Getz]

Colonial........beware....you said you were "learning" a lot about shooting in this forum.......there are good teachers, and
there are some that are, well, not so good................Don

[stuart cee dub]

...and  after you  convert from 2f to 3f check your group size .
Some guns defy the rules and will not work with 3f at all.I have a 58 that loves 3f and a .45 that shreds patches when using 3f insisting on the dirtier 2f  GOEX.
Just the opposite of the normal rule of thumb with powder and bore size that Roundball refers to ,and correctly so as a generalization .
But I was going for the smallest group size as the only desirable outcome, maybe you want more energy per grain , less cleaning between shots ,a cleaner bore or just to use less powder.
During one of the periodic powder shortages a few years ago when the plant blew up there seemed to be more 3f than 2f so a lot of people worked up loads using 3f instead of the harder to get 2f , found 3f worked better ; they used less ,and never switched back .
I would be interested in your results .
regards Stuart
 

[rsells]

Take the time to work up a load and use the load that yields the best group.  Adjust the sights if need be, and spend a bunch of time shooting and get to know where your rifle prints at different ranges.  Takes a bit of time, but is a lot of fun and gives confidence in the rifle/charge combination.
                                                                              Roger Sells

[beleg2]

Hi,
Here in Argentina we do have no this problem deciding with powder to use.
We can only get 3F Inkael powder! 
So it works OK for every one. 

Martin

[Colonial Riflesmith]

Hey B2, sounds like the "KISS" principal. 'Keep it  Simple'.

I'm always into learning new things, and how other shooters perform. I will never change my load though. I've been using the same load for too long '65gr 2f in my .50', and it works too well for me.

[Jefferson58]

Thanks for all of the info. folks. I will work on some loads and see what happens. At least I have an idea of where to start.

Jeff

[longcruise]

Thanks for all of the info. folks. I will work on some loads and see what happens. At least I have an idea of where to start.

Jeff

If you take the time to shoot some 3f loads till you get them impacting at the same point as the 2f loads and report back here with the results you will have educated us more than we have educated you!!;->

[Daryl]

I prefer to shoot what the gun wants to shoot. It tells me how much powder I need to use to achieve the accuracy I demand.  To me, shooting a light load just because I'm cheap would be a waste of powder.

 I develop accuracy loads for my rifles using both 3F and 2F - I find in the winter time I need 60gr. of 3f to shoot well in the .40, but have to increase that to 70gr. 2F to get the same accuracy.  In the summer, I get away with shoooing 55gr. 2F in the .40 - it loves this light load then, but not in the winter - go figure.   When I chronographed those 2 heavier loads, I found the velocities to be very close.

 My .45 likes 75gr. of 3f and 85gr. of 2F - didn't chronograph, but expect the speeds to be the same.

My .69 DEMANDS a good healthy(or unhealthy) charge to shoot accurately. It will not shoot a group inside 4" at 100 meters with less than 140gr. of 2F, but will shoot 1" to 1.5" with 165gr.  Yeah, it's a man's rifle.  but - I wimp out and only shoot 82gr. of 2f on the local trail so I don't break too many targets each time through.  82gr. of 2f will shoot a nice, round 6" group at 100 meters - about 8" low - useless - absolutely useless.

[Pete G.]

I've seen some of the pictures of Daryl's winter. The rifle knows better than to play outside.  
Personally I have started using much lighter loads since I started putting shots over a Chrony and then doing the math of what you really get out of a heavier load.
Looking back at some of the loading that was advocated in the 70's I can only say "Holy Shite Muslem".
I have settled in on most loads that are somewhere in the neighborhood of 1-1/2 gr per caliber ie. 50 cal=75 gr. Like most things in this sport it is not a hard and fast rule. Accuracy seems to more of a function of patch/ball/lube combination. Find a combination that shoots well, then change the grains of powder for range and intended target. Knocking holes in paper at a fixed range doesn't take much, but knocking holes in a game animal at estimated ranges takes a bit more. Now back to the original question; I have noticed that velocity increased about 18 to 20% from 2F to 3F. I don't know if pressure is a linear progression or not, but obviously more velocity requires more pressure. At lower loading levels it probably doesn't matter much, but as you get into heavier load it can put a marginal load into dangerous territory.

[Daryl]

  I don't know if pressure is a linear progression or not, but obviously more velocity requires more pressure. At lower loading levels it probably doesn't matter much, but as you get into heavier load it can put a marginal load into dangerous territory.

 When shooting round balls, it is almost - almost - impossible to produce the high pressure that shooting slugs produces, yet some feel a 120gr. to 140 2f charge in a .50 or .54 with around ball is an overload - NOT. -  A 100gr. 2F charge and a 450gr. slug in either bore size is considered normal, yet will be producing double the pressure of the round ball load. People don't seem to realize that shooting slugs produces high pressure - just witness the data from Accurate Arms with their Sharps data.  90gr. 2F and a 450gr. slug in a .50 produced 24,000PSI - that my friends is at the upper limits for a heavily built cap lock. A normal 405gr. load in a .45/70, with 70gr. of 2F produces 22,000PSI & a 4.5x3-1/4" load with a 450gr.slug and 140gr. 2F produces 30,000PSI- yet, people put slugs in their in lines with 15/16' barrels and in period-type muzzleloading rifles, along with 150gr. of 2f duplication or normal powder and fire away.

I've never seen a load printed here when used with a round ball that I would consider heavy, let alone dangerous - we shoot round balls patched in cloth, not heavy elongated slugs which obturate into the rifling and create extra friction and pressure.  Dangerous with patched round balls - not likely- in my opinion.

[northmn]

I looked in the Lyman's handbook as to pressure increases for a roundball.  Surprisingly for a 45 RB with a 28 inch barrel, if one uses 2f, at the higher, what we would call hunting velocities, such as above 1900 fps the 2f takes a jump and generates more pressure.  90 grains of 2f showed 1882 and 12,100 CUP and 100 grains of 2f 2008 and 15,100.  70 grains of 3f gave 1994 and 13,680.  At some point it is possible that an increase in total mass of the charge in a smaller bore can give a pressure jump.  At lower velocities 2f was generally lower pressure, but not significantly so.  Problem with the Lyman tables is that at about 10,000 LUP they jump to CUP so that one cannot say the pressure doubled etc.  Both have been discontinued as pressure guidelines.

DP 

[jmforge]

  I don't know if pressure is a linear progression or not, but obviously more velocity requires more pressure. At lower loading levels it probably doesn't matter much, but as you get into heavier load it can put a marginal load into dangerous territory.

 When shooting round balls, it is almost - almost - impossible to produce the high pressure that shooting slugs produces, yet some feel a 120gr. to 140 2f charge in a .50 or .54 with around ball is an overload - NOT. -  A 100gr. 2F charge and a 450gr. slug in either bore size is considered normal, yet will be producing double the pressure of the round ball load. People don't seem to realize that shooting slugs produces high pressure - just witness the data from Accurate Arms with their Sharps data.  90gr. 2F and a 450gr. slug in a .50 produced 24,000PSI - that my friends is at the upper limits for a heavily built cap lock. A normal 405gr. load in a .45/70, with 70gr. of 2F produces 22,000PSI & a 4.5x3-1/4" load with a 450gr.slug and 140gr. 2F produces 30,000PSI- yet, people put slugs in their in lines with 15/16' barrels and in period-type muzzleloading rifles, along with 150gr. of 2f duplication or normal powder and fire away.

I've never seen a load printed here when used with a round ball that I would consider heavy, let alone dangerous - we shoot round balls patched in cloth, not heavy elongated slugs which obturate into the rifling and create extra friction and pressure.  Dangerous with patched round balls - not likely- in my opinion.

Are the higher pressures in those slug guns all about the tight fit of the projectile or is some of it a factor of getting 2 1/2 to 3 times as much mass with a lot more bearing surface moving initially when compared a round ball of similar caliber?

[Daryl]

Good question, Jim - we know the straigth cases liek the .45's and .50's produce identical numbers for CUP and PSI - ie: 22,000CUP IS the same as 22,000PSI. this only holds true for the straigth cases and does include handgun rounds like the .45Colt, 44mag, etc. - same goes frothose 13,000CUP pressures, being same as 13,000 pounds per squaer inch.

Therefore, we know the various .50 and .45 cases, long and short using those heavy bullets and charges, which are identical to what guys are putting through those inline rifles & what some guys put through flinters and caplocks, are making huge numbers - up to 30,000PSI.  that is a LOT of pressure and explains why nipple holds burn out quickly in slug guns.

The high pressure developed by the slugs is due to the friction fit as well as the weight- inertia of getting the bullet to start & keep it moving.

Round balls are much lighter per calibre and therefore produce much less pressure.  Note in Lyman's data, the pressures developed with the slugs in each calibre, in comparrison to round balls to see this.

[jmforge]

Good question, Jim - we know the straigth cases liek the .45's and .50's produce identical numbers for CUP and PSI - ie: 22,000CUP IS the same as 22,000PSI. this only holds true for the straigth cases and does include handgun rounds like the .45Colt, 44mag, etc. - same goes frothose 13,000CUP pressures, being same as 13,000 pounds per squaer inch.

Therefore, we know the various .50 and .45 cases, long and short using those heavy bullets and charges, which are identical to what guys are putting through those inline rifles & what some guys put through flinters and caplocks, are making huge numbers - up to 30,000PSI.  that is a LOT of pressure and explains why nipple holds burn out quickly in slug guns.

The high pressure developed by the slugs is due to the friction fit as well as the weight- inertia of getting the bullet to start & keep it moving.

Round balls are much lighter per calibre and therefore produce much less pressure.  Note in Lyman's data, the pressures developed with the slugs in each calibre, in comparrison to round balls to see this.

One of the things that made me ask was that Cunard warns that even their platinum nipples can get burned out with heavy loads of Swiss 3f.  From what I have read, Swiss 3f is not only faster burning in general like all 3f powder, but even more "energetic" than other brands, so I figured that it is trying to move that projectile RIGHT NOW even more than other grades and brands of powder and the inertia of the projectile allows that big pressure spike.

[Daryl]

One of the things that made me ask was that Cunard warns that even their platinum nipples can get burned out with heavy loads of Swiss 3f.  From what I have read, Swiss 3f is not only faster burning in general like all 3f powder, but even more "energetic" than other brands, so I figured that it is trying to move that projectile RIGHT NOW even more than other grades and brands of powder and the inertia of the projectile allows that big pressure spike.

Forsyth addessed this in his book - when mentioning grades of powder back in 1850's.  That the best accuracy with slugs ("the accursed minnie") was obtained with slower, ie; larger grained powders(ie; slower to burn) as they didn't try to start the bullet into such high veloctiy at the start but allowed the bullet to fully engage the rifling before high velocity was imparted to the projectile.  he also mentions that the faster powders were more suitable for round balls, as the ball's hold on the rifling was already assured by the 'substancial' patch.

[northmn]

1F powder used to be used a lot in shotguns and in large BPC.  I wonder if even 2f isn't a little "hot" in these long range ML's.  Another thing is that in Ned Roberts book on muzzle loaders, he mentioned hunting with a Billinghurst 45 double using 70 grains of powder and a 480 grain bullet.  Long range shooters also tend to load more powder than that.  What was the Whitworth loaded with as I doubt they used platinum nipples?  When I chronographed some loads in various calibers, I noticed that while 3f gave the same velocity with less as the Lyman book indicated, my shot to shot variation was greater with 3f.  I think mine was about a 20 grain variation for equivalence between 3f and 2f.  At longer ranges, maybe beyond RB efficiency, shot to shot variation can be a problem. 

DP

[jmforge]

1F powder used to be used a lot in shotguns and in large BPC.  I wonder if even 2f isn't a little "hot" in these long range ML's.  Another thing is that in Ned Roberts book on muzzle loaders, he mentioned hunting with a Billinghurst 45 double using 70 grains of powder and a 480 grain bullet.  Long range shooters also tend to load more powder than that.  What was the Whitworth loaded with as I doubt they used platinum nipples?  When I chronographed some loads in various calibers, I noticed that while 3f gave the same velocity with less as the Lyman book indicated, my shot to shot variation was greater with 3f.  I think mine was about a 20 grain variation for equivalence between 3f and 2f.  At longer ranges, maybe beyond RB efficiency, shot to shot variation can be a problem. 

DP

The references that I have seen for Purdey express guns and other slug guns from the late percussion era said they used Number 6 powder, which is best as I can tell, was a coarse grain powder......maybe like modern Swiss 1.5?