The one thing to remember about ball in choke bore guns is the ball must fit the choke, not the bore. The "Not for Ball" marking on early guns simply meant they were not to be fired with a "Bore-Fiting" ball. This mark was changed to one of simply "Choke" as there was confusion & many took it to mean No ball at all could be fired. Best accuracy is "Apt" to come from a cyl bore with a well fitted ball, but for a choked gun just make sure the ball/wad combo will pass through & try it. Just might be surprised. As I understand it the biggest problem with a smoothbore firing ball is somewhat akin to a baseballer's "Spit Ball" IE it sometimes can "Break" at an unpredictable angle to it's flight line. The round ball from a smooth bore gained much of it's bad press from the old military muskets which for rapid loading (Assualt Rifles) were loaded with much undersized balls which rattled down the bore in a hap-hazard manner, leaving the muzzle with different spin directions depending upon last contact.
