7773f or 2f?

[conwaydave]

I bought 3f to shoot in my Bighorn, and was just told it is more of a pistol powder and 2f is for long barrels? Or, I should at least decrease the powder by 10 or 20 grains? I am very new to ML, and any help would be great.

[Dirty Mike]

3 f is fine many shoot it I used to but have switched back to 2 f

[JimmyHoffa]

F--Cannon powder and large rifle loads (.45-120 Sharps).  Very Coarse large grain, slow ignition produces a lot of gas for good constant pressure.
FF--Rifle/Shotgun (blackpowder).  Coarse but smaller than cannon, larger than pistol powder.  Good ignition time, but less gas produced for energy than cannon powder (F). 
FFF--pistol and small rifle powder (like the .36 cal blackpowder squirrel rifles).  Faster ignition but even less power (but not needed as .36 cal and .45 cal roundballs accelerate more easily).
FFFF--priming powder.  Very fine powder.  Not much work derived.  Used mainly in flintlocks to ignite the main charge.  Also used with (F) in black powder rifle cartridges where primers alone can't get the main charge ignited without delay.

[Sabotloader]

I bought 3f to shoot in my Bighorn, and was just told it is more of a pistol powder and 2f is for long barrels? Or, I should at least decrease the powder by 10 or 20 grains? I am very new to ML, and any help would be great.

That is all I use in all of my cap guns including the 54's.  It burns a lot cleaner and is easier to ignite with a cap because it is so fine - for me that is important in the really cold temps we hunt in.  Velocity and accuracy have been great.

But!!! you are the general rule says.... but remember T7 is not really a Black Powder it is a sub with some different characteristics...