I'm confused about the multiple purchases of deadblow hammers (if they're the same weight) but I'm not going to ask. I will ask if the people buying them own other hammers (i.e. a drilling hammer). Deadblow hammers aren't really great for what I think people are using them for (dislodging gasketed parts, hammering out hubs, rust smacking, etc.); they're very awkward to weild for heavy hammering, good for setting parts. But hey, to each their own.
Consequently you can buy a nice one piece estwing drilling hammer (2 or 3 pounds as I recall) most places for around 30 bucks which some people might be interested in if they want to do some of the stuff I listed a bit quicker.