I have a 28" 870 SM and I have several boxes of old remington 3.5" hevi #4, 1 7/8 oz shells that I may try this year. I currently shoot hevi #6 or #7 through a .665 JH and get great patterns, I just wanted to try something different. The hevi #4 should have plenty of energy at 40 yards and I did shoot one out of the .665 JH at 40 yards and got over 120 in a 10" circle. Should I try a tighter or a more open choke with the #4 hevi? I usually carry a 20 ga or my 835 in the spring but usually use this 870 in the fall season.