In lead shot, both 5 and 6 are very popular among turkey ... The answer is to pattern your gun and see how it performs with each shot size. You can evaluate patterns by how many hits your shell ...

If fact, this gun consistently patterns better than any .410 I’ve shot. Whether it’s fed No. 4s and 6s from Winchester, Federal TSS No. 9s, my 7-1/2 turkey handloads, or No. 9 lead handloads ...