Hi Bill,
Whatever is on the list do NOT qualify. ALL the rest do. Since there was so many different calibers in the past ( some only historians and antique gun experts know the existance), its easier to tell the caliber who dont qualify as they are more common ,basically known by everyone and the list is much shorter.
manufactured before 1898 that can discharge only rim-fire cartridges, other than 22 Calibre Short, 22 Calibre Long or 22 Calibre Long Rifle cartridges;
manufactured before 1898 that can discharge centre-fire cartridges, other than a handgun designed or adapted to discharge 32 Short Colt, 32 Long Colt, 32 Smith and Wesson, 32 Smith and Wesson Long, 32-20 Winchester, 38 Smith and Wesson, 38 Short Colt, 38 Long Colt, 38-40 Winchester, 44-40 Winchester, or 45 Colt cartridges
Thats why You can get antique .455 Webley modified to shoot .45 acp and still qualify as Antique. The caliber .45 acp is NOT on that list.
So If it was MFG prior to 1898, and the caliber doest NOT appear on that list It does qualify as ANTIQUE.
Please anyone correct me if I am wrong !!