20 grains a wad and then ball will be no problem, press it down. The gap between the ball and the end of the cylinder is not a safety issue, some believe it is an accuracy issue. The safety issue comes in to play in smaller loads, where there is a possibility of an air gap between the powder and ball because the loading lever is incapable of seating the ball all the way down. I have the Pietta Remmy and mine will still seat a ball firmly against the powder with a 15 grain charge, I have not tried anything smaller.Keep in mind these guns were designed to fill the chamber with powder, leaving enough room to seat the ball, so the levers were not designed to ram the ball down on a 10 grain load. IIRC 35 grains will fill my cylinder to the top, so that 30 grain load with a wad and ball is probably your maximum load.