Roland's guns are described as "carefully weighted to his hands." Although they once belonged to his father, the guns were adapted to fit Roland's specific needs. When the guns came into his hands, "a plate had been added to each."
Roland's father, Steven Deschain, "had been lighter and not so tall" as our gunslinger. This is interesting because Roland is depicted as physically lean, so his father must have been a fairly small man (although, to be fair, Roland is also considered to be a pretty tall guy, so Steven was probably not what one would call small ... although bearing in mind the relationship between his wife Gabrielle and Marten, it's kind of impossible not to think in a certain direction here).
It's impossible to ignore the fact that, in terms of physical stature, Roland is superior to his father. Steven Deschain, once ruler of Gilead-that-was, is not able to effectively shoulder his burden. Interesting that Roland's very height and weight give the reader early (very early ... we're talking page four) indications that he is able to carry a much heavier load.