What is the model and manufacturer of the gun you have. You can look at the hinge pin and if very much wear is visible that might be all it takes. 70 years old is not old to me, I shoot many that are older than that. If it was a quality made gun that you want then fix it, have it fixed. With very few exceptions, a single barrel from the 1950s is not viewed to be worth even 100 $ by most people. So two hours of gunsmith time is “more than its worth”. Not!