Built my first rifle, a Green River Rifle Works .54 Leman in '83. Used it for deer and gravitated to competition. Although a .54 is definitely not the ideal offhand target gun, it won the South Carolina State Championship four times and placed in the top three five more in the '80's and early '90's. Bought a Bean style .36 about '92 for head shooting squirrels and found it to be quite accurate on paper with a .355 ball so began using it in competition. Not great in the wind, but it won the S. C. State Championship several times, too. Then I lost the keenness of eyesight at about age 50 that is SO necessary for fine competitive notch and post sight work, and kinda lost interest in paper punching.
In '83 and '84 I competed at Friendship in offhand rifle and buffalo rifle. Had built a 13# 15 oz. .45 cal buffalo rifle with Redfield 75 and front aperture that is superbly accurate. I have targets I have shot with it using a .455 ball that measures 5/8" inch ctc for five shots. Many will deny that a patched round ball can do that, but I know better. Many other old bench and buffalo shooters do, too.
Bought a 16 ga. Powell double at Friendship in '84 and killed many limits of doves with it here and in S.Carolina with 1 oz. of 7 1/2's over and equal volume of 2F Goex. Sold it a few years ago to a friend and was recently given an original Manton, (not a Joe), 16 ga. double by a dear friend and his wife. It is in nearly unfired condition. Perfect bores and absolutely no pitting around the nipples. Haven't tried it out yet, but will eventually on early season doves this year.
Agree with Greg on the dismal BC of round balls, that is a scientific fact. But not on the poor terminal ballistics. My years of experience with them on game from squirrels to whitetails has been quite different. I have found that the cohesive nature of pure lead, and that is all I use, causes the percentage of weight retention to be quite high. That is, when you don't have complete penetration. And penetration can be phenomenal for a projectile of such low sectional density. In one instance I shot a 220# buck in the front of the chest at 80 yds. with a 237 grain .535 ball ahead of 120 grains of FFg. It penetrated the buck lengthwise and exited underneath his right hind leg never to be seen again. Unbelievable wound channel. A .45 cal. ball ahead of only 60 grains will exit a big buck shot sideways through the ribs/lungs. When the balls do hit bone they deform, and become even more deadly as they plow on, retaining much of their original weight. There's never been a perfect bullet made, and round balls have many faults, but I've never found terminal ballistics to be a problem. But then, I've never tackled dangerous game with one. Many others have, though. I would agree that compared to modern jacketed bullets under many conditions the round balls will come in second. But a deer or smaller thin-skinned game shot properly with one will never know the difference.
My experiences and those of my acquaintances only. Stan