Yep and the II was made to fit certain mags that the heavys wouldn’t fit...JSB is just covering as many different mags as possible with these two pellets."Dirte"For starters.....The shape is different. The Heavy is longer and does not fit in some magazines. I'm sure others will have more detail between the two. Pics here. http://www.airgunnation.com/topic/25-jsb-heavy-quick-review/page/2/