Just a word of caution. If you use a hardware store dowel for a ram rod, make sure the grain is straight, try to get hickory. Some dowels seem to be made of a softer wood like poplar or cheaper maple, with knots, crooked grain etc. Crooked grain in a ram rod can lead the a large splinter into the hand when it splits.
Frankly, our local hardware stores have some pretty crappy dowels. I would wrangle up some real straight grained Hickory mail order if need be, Or, I would make one from brass, delrin or stainless before the local offerings.