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From FF to FFF

3196 Views 11 Replies 8 Participants Last post by  Bunky
Is there actually a formula for this? I'm thinking of switching from 2f to 3f and then using 3f in the pan too. Everything I find is cut back about 10 grains or other things say cut back 10% (about the same in most loads). But I have yet to find any chart or load data that discuss 3f loads or compare the 2. Anyone have such a chart?
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It depends slightly on caliber. I assume you mean a 50 cal, hunting style gun. It also depends on brand. Switching from Goex to Swiss in the same granulation nets higher velocity. Assuming you stay with the same brand, going from 2f to 3 f will usually, (but not always) produce higher velocities when compared grain for grain. 3f tends to burn a bit cleaner in most guns. In medium to longer length barrels, switching to 3f can have lower velocities with light to moderate loads. (The 3fg is consumed before the ball reaches the muzzle and friction starts to slow the ball down. )

As a rule of thumb, I'd say the difference of about 10% is probably close, but each gun is different. percussion is different than flint, etc.

using 3f in the pan is slightly slower to ignite the gun. But it is a matter of perhaps a hundredth or two of a second.
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Using Goex in a .50 cal TC Renegade
A renegade has a 26 inch barrel as I recall. You should get better more complete burn with 3fg, but keep it moderate. Over about 80 grains starts to burn powder after the ball exits the muzzle.
Chuck at Dixons once told me to use 80-85% volume of FFFg in place of FFg to start, then modify accordingly.

100gr. FFg = 80-85gr. FFFg
80gr. FFg = 64-68gr. FFFg, so use 65gr. since the measure is in 5gr. increments. Couple of flakes more or less if you want to be precise.

And if you are planning FFFg in the pan because you dont want a whole can od FFFFg for the pan, shops have started splitting the can. Dixons sells FFFFg in quarter can (1/4 lb.) incremets in a squeeze bottle.
You may change but your gun might not like it or it could like it better.Use what gives the tightest groups.
Some of my 50's like FFFg others demand FFg.
my .62 cal smooth bore really likes FFFg. spend some time at the bench, you'll find out which works better for you.
There are many posts on this topic and switching is a personal choice---I like 3 F much better since I can shoot it and prime with it. I would start your load low --say 50 gr at 15 yards just to see where the thing shoots. Then go back to 25 and shoot 3 more. Now adjust your powder up from there at 25 then 50. Depending on the person and time you have try 10 yard increments out to where you feel comfortable.
I use FFg in barrel and pan, No problems at all, Never plan on changing works for me. If you want to buy 2 different powders. Go ahead, In fact this kind of weather FFg is the best for pan.
Back in the 80's, one of the Lyman black powder manuals did instrumented testing of 2f vs 3f in a .54 cal rifle. It included velocity and pressure data. The short answer was that 3f worked fine, and you could use less of it for the same velocity.
Lyman even lists both FFg and FFFg max. loads in their manuals. They show 110 gr. of FFg to 90 gr of FFFg. That falls in line with the 15-20% reduction Dixons mentioned.
3F vs 4F for priming----in damp weather the 4F has a tendency to 'goop' up .... the bigger the grains thus allowing more oxygen between particles seems to burn better without as much fouling at the lock on multiple shoots (IMHO) I dont use the 2F so I would not know but if it works well for you dont change it... That means you to only have to use one powder.
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