Alexander, I have the same problem with a relined '73 Winchester. The bore was supposed to be .428 but was .431, and bullets that size in any brand of case chamber hard. It is easier to work on a revolver cylinder than on a '73 chamber, so if you can find a chambering reamer (not the throating reamers that most of the replies are talking about) with a larger neck section, it should be fairly easy to open them up. I know some finish reamers can be pulled into the chamber using a rod inserted through the muzzle. I don't know if oversized ones are available for the 44-40.