I haven't shot a .50 caliber rifle in a while, but before I sold my .50 caliber flintlock, I had settled on and was using .480" balls with .015" patches. I felt that I was giving up some accuracy, but the trade-off was worth it for me with the ease of loading. I don't shoot much beyond about 50 yards with open sights due to visual limitations, and close range accuracy with this combination was good enough for me.
This has been discussed several times over the past few months. If you put ".480" in the search box up there in the upper right corner of your screen, it will bring up multiple conversations on the topic. It always seems to boil down to each individual following his own path and setting his own standards. In
The Kentucky Rifle, Captain Dillin reported many old shot pouches contained two sizes of balls... One for best accuracy and one for a quick reload. Don Bruton, a master flintlock rifle maker and knowledgeable historian, also discussed this in his flintlock shooting video ( which I highly recommend). On the other hand, James R. Mead, an old-time round-ball muzzleloading buffalo hunter, described taking follow-up shots with a bare ball, with no patch. He was a very successful still-hunter, not a buffalo runner, and in his time (1850's -1870's) with his skill, he could get pretty close. On one occasion, he described killing over 30 animals, all his skinners could handle in a day, from one position about 30 yards from the herd. Walter Cline, who was a fanatic in pursuit of ultimate accuracy and documented his research in
The Muzzle-Loading Rifle, Then and Now, said best accuracy was achieved when using a ball that could just be pushed down the bore under the weight of the ramrod, which I'm thinking would be just about bore diameter. If I remember correctly, he favored a linen patch of about .015" with that size of ball for best accuracy.
However, it is my understanding that hunters and the military used patched balls of smaller diameter than is recommended now. Lewis documented that .54 caliber American military rifles intended for patched round balls, including the various "common rifles" and the M1841 Mississippi rifle, used balls of .525" diameter, or .015" under bore diameter. Military smoothbores used balls we would consider egregiously undersized, such as .650" balls for a .69 caliber musket.
Anyway, the point being that there are a lot of ways to shoot these rifles, and we each follow our own path. There is historical and empirical precedent for shooting tight balls and smaller ones. I have another .50 caliber rifle I have not yet shot, and when I get around to shooting it, I expect to bring a bunch of .480" balls and several different thicknesses of patches to the range with me.
As a final thought, your ".50 caliber" rifle might not actually be .50 caliber. The old Numrich ".45 caliber" barrels typically measured around .443", I believe, and some of the more accurate .54 caliber Hawken copies that came out of Italy were actually .53". Earlier this year, I got a Hawken half-stock, built by Mr. Bergmann around a "new old stock" GRRW barrel in nominal .54 caliber. These barrels, while well made and accurate shooters, are notoriously inconsistent with regard to bore size, and they frequently run small. The first round I loaded in it, in a clean barrel, was a .528" ball in a .017" ticking patch. I had to hammer it all the way down with a mallet! Subsequent shots were fired with .520" balls, which still needed some effort to seat but were within acceptable parameters.
The bottom line is that if you like .480" balls in your .50 caliber rifle, by all means shoot them! My only concern would be that if you hunt, you'll want accuracy and energy adequate for making killing shots on the game at the distances you'll be shooting.
Best regards,
Notchy Bob
P.S.:
@cajun , I think Midway USA has .480" Hornady round balls available and on sale right now.