Only have the Mossberg Sa-28 but patterned the .520 and .525 with #7 and #9 last night, as a comparison. Pics were terrible but there was a noticeable difference with the different sized TSS. The .525 was the best on the #7's and the .520 was better with the #9's. Just a little info to pass along. I think most states allow #9's but for those that dont, in my setup the #7's were better with the .525. Good luck and God Bless. Z