I was thinking of the LCR-X in .38 spl +P,
which weighs 15.7 oz.
There *IS* a .357 mag version, but it's 21.3 oz,
and considerably more expensive, too.
357 snake shot holds a lot more pellets though, and as a defensive round it beats 38spl hollow. You could actually use it against a bear with the right bullets if needed. I can't see 5oz being a big deal, and as that bear is charging you I doubt you'll be saying "but at least I saved $100".