Just a heads up. If your going to use smaller shot, like #6. You will probably get much better results out of the .660 JH, especially with a 21" barrel. I've been there, done that. I never shot the LB's from that combo, but that's what worked best for other lead and Hevi loads for me. I started with the .665 and then went to the .660. I also was shooting a 3" gun, not the 3.5". You may just have to try it, may work good out of yours.