I suggest a good reloading manual. Lyman shotgun book is good, I like the BPI Advantages book as it has data for 2.5" shells and ITX shot but does sell it's products. Loadbook 20, 28, 410 has excerpts from most of the individual manuals plus data from powder companies.

Link to Loadbook.

https://www.precisionreloading.com/cart.php#!l=LB&i=00003

http://www.loadbooks.com/Store.html

Last edited by oskar; 08/31/15 07:16 PM.
After the first shot the rest are just noise.