00 is 33 and 0 is 32. Used a 319 in my 32s with good luck. Had one in Douglas and one in Montana barrels? Most buckshot sold is hardened with a touch of antimony. Track of the Wolf now lists pure lead buck shot in 0 size for $24.50 for 5 pounds. You may find this easier than casting your own. I bought 5 pounds of #3 from Track and do not own a mold. There is a slight variance in sizes of about .003-.004 but most run at .248. You will get the same thing casting, and whether it matters unless you are shooting 100 yard bench I do not know. I do not own a mold for the 25 as the cost of the mold would take a lot of casting to match the cost of the shot. Even swaged ball at about $8.00 per hundred would give you 200 shots at the cost of a Lee mold. For some its part of the do it yourself thing, for me it gives me more time to do other do it your self things.
DP