Rifle moulds on the other hand, for me need to be .005" smaller than the bore - thus in a .62 rifle, I'd use a .615" ball. Here, Lyman moulds, my normal choice are well over $100.00- so the Tanner mould at about $30.00 Us is the best, price wise.
I use 3F or 2F in .40 through .69 in rifles. I use 3f in my .36, but will probably find a 2F load it likes, just in case I run out of 3F. The larger bores, .50 on up, seem to shoot best with 2F - for me - that is, they shoot more accurately than with 3F.
There are no hard and fast rules for powder charges. You should experiment with different loads, perhaps ball sizes and patch thicknesses to find the combination YOUR rifle likes best - IF your rifle's BEST accuracy is important to you.
Note, in the bore sizes such as .50 and above, 3f will generate MUCH higher pressures than will 2F - at the same velocities.
That is for example, at a velocity of 1,600fps, the 3f load producing this speed will generate more pressure inside the barrel, than will a charge of 2F that produces 1,600fps in the same rifle. Also note - it takes MORE grains weight of 2F to generate the same speeds as generated by any load of 3F.
For guys loading 'slightly' weak/thin patch combinations, 2f will most likely shoot more accurately due to the lower pressures generated for any given load. The higher the pressures, the more likely the chance of gas blow-by burning past the patch and ruining accuracy.
For those who think a patched ball does not SEAL the bore, one need only to be standing beside me if I load my .69 without lifting the hammer to 1/2 bent position.
If the hammer is down on a spent cap, I cannot seat the next ball all the way- about 5" short of the powder - the air pressure inside the bore will push the rod and ball back up the bore- almost out, if I let go of the rod.
When I pull the hammer to 1/2 bent, the pssewwwwwwwwwww out the nipple shows there was a LOT of air compressed between the patched ball and bottom of the grooves.
Some math-oriented lad could compute the compressed air volume - Pi x R squared x length? .702 (1/2 .690 bore and .714 groove) divided by 2 = radius x radius x Pi x 30" = 11.6cu. in? Compressed into about 4" length - is that right? I don't know - maybe - enough to say, the patch makes a pretty good seal.
After releasing the pressure, I can push the patched ball down onto the powder.