I've shot doves a few times with a muzzle loader. I finally came to my senses and started shooting black out of cartridge guns....

Tip don't stop to reload untill you shoot both barrels because when you do doves will trying to land on your head and two barels load about as fast as one.
Reloading can be done fairly quickly with a shot snake and a proper powder flask. Myself I like the Irish measure on a shot snake....I "think" Highsmith prefered the English measure.