You can buy federal 3.5 magnums #7'sfrom Macks Prairie Wings. This load is absolutely amazing. I shot #5's last year and after hearing about #7's total kinetic energy, I made an adjustment and bought me a couple boxes. Out of my browning gold this load is AMAZING! I'm going to include a link below, which is where I bought my shells from. Good luck to all!

http://www.mackspw.com/item.asp?im=FEDPHT191+5&d=Federal_Premium_Magn um_Shock_Turkey_Load_12_Gauge_3_1%2f2_Inch_1_7%2f8 _Ounce_Box

Sincerely,
David ellis