The swabs want to be fairly tight fitting.
I mad mine using synthetic sheepskin around a 1.125 inch wooden dowel, using "Barge Cement" as an adhesive. The glue has held up really well. There is a single brass nail in the end, helping the glue hold the folded-over sheepskin in place
The swabs are a bit on the loose side, especially after a year of use. If I can find a 1.250 dowel in some local hardware store I will make the next ones out of that.
I used a plastic bottle about 2.0 in diameter. It is a chem lab type container... nothing you would find in a grocery store. I like it because it is slipery and releases the aluminum foil well.
As far as the rammer, I guess if it is bigger than 60-ish% of the bore diameter it doesn't matter exactly what size. My gun is a mortar, and I made a "U-shaped" rammer out of 1" wooden dowels (to remove any need of getting in front of the bore), some brass 90 degree fittings, and a brass nipple. There is a rubber "foot" on the ramming end (like you would find on the end of a cane. That makes the OD of the ramming end about 1.75" or so.
