The more I research I think the barrel stub might be the way to go, I found a place (eagle view arms) which sells stubs for $95, just need to get someone to do some lathe work and we might be on to something.
Yes I know it might not be cost effective but this barrel was given to me by someone very special and rather than just let it sit there I would like to put it to use for my son to use in squirrel season this year.
It would be the icing on the cake for him. (he's 9 yrs old)