Lobo pretty much said it all, although I would not worry much about firing +P in a steel J frame. I have nine fixed-sight J frame .38 Spl revolvers. Six of them are sighted for 125gr (110 gr STHP is also OK). At present, my favorites are the three that shoot 158gr to POA. I do have a reasonable supply of 125gr Federal Nyclad, and a couple of boxes of 110gr STHP. I haven't yet checked out the 135gr GDHP +P, mainly because it is IMO appropriate only for my steel-framed revolvers, which are not quite as handy in some ways as my Airweights.