My good friend and neighbor, Steve Conover had held serval of the World Records.He shoots for Indian Creek Shooting systems. Serval of the IC guys have either won World Championships or set World Records shooting his guns. Hevi-13's are awesome. Steve put 250 pellets in a 10" circle at 40 yds, with a stock Browning Bps with an Indian Creek choke. Last night I put 208 in a 10" circle at 40. I slightly missed to the right or the count would have been higher. Shooting a Mossberg 935 & Indian Creek choke. I was shooting a Hevi-13 3.5", 2&1/4 ounce of #6's.
When chosing a Hevi-13 load there 4 to pick from, but only 2 are good. Only shoot the 2oz load in the 3" shell and the 2 & 1/4 oz load in the 3.5" shell. Don't waste your money on the other 2. The 3" shell is bronze & the 3.5" shell is gold. If you can find the old white shell, buy what you can. It is an awesome shell.