I use 416 proshot brushes in the 404 or worn 45 cal as 500 nitro suggests
500 brushes in the 470
338 brushes in the 318 wr
worn 30 cal brushes in the 25.

I buy proshot brushes from the large US mail order companys in packs of 10 at about $1.50-2.00 each.
I treat them as a throw away item once they have served there purpose,not something to be treasured for a life time.
good shooting
sbs470