How much lead shot is in a 7.5 12 gauge shell bird shot shell?

A correct answer would depend on the oz of the load in the shell

1oz =345

1 1/8 oz=388

1 1/4oz= 431

1 3/8oz= 474

all + or - by a few one way or the other. 7.5 / 8 Shot Shells are considered to be

Target / Game Loads. They have a relative LIGHT LOAD OF POWDER charge to them.