Some of the older .44 Rugers had either a design or manufacturing defect, and would jam.
Ruger recognized the problem, and would repair it free of charge if the rifle was returned to them. I do not know if Ruger ever made the solution to the problem public so that gunsmiths could correct it.
What I am speaking of was it the time period your rifle was built. I do not know if Ruger will still correct the problem or if they will tell you how to do it, but the problem was real during this time period.