I have an old Canadian Winchester 840 in the back of the safe, but it's still a bit long and heavy more my 10 year old grandson. It has a 28" full choke barrel. I know the subject has come up before, but I'm having trouble with the Search function. I'd like to shorten the barrel and stock for him. What can I expect to pay to have the barrel cut down and threaded for a choke tube? Thanks.