I've been loading Win AA hulls with birdshot for many years, but now I have a question; is there any particular difference in loading the same weight of buckshot as birdshot in the same recipe?

In a cylinder bore shotgun, could I load (for example) 1 1/4 oz of buckshot (of proper size) in place of 1 1/4 oz of birdshot?

Check a reloading manual!

AR is the world largest and also the world's most underpaid research department but I think everyone here will tell you to check a reloading manual.

BTW how many ounces in commercial load? I think they are sold by the number of pieces of shot...could be mistaken.