In the functional and safety senses...
there is no problem, if, as you say, the LR round chambers freely. If the original barrel was simply rechambered for the longer cartridge, the slow rifling pitch for the short cartridge will not properly stabilize the heavier LR bullet, and the bullet will keyhole at any range - no accuracy is possible. If the barrel has been re-lined, as well as re-chambered, it is likely that the liner has the proper pitch for the LR, and, if the installation and chambering were properly done, should shoot well.
PRD1 - mhb - Mike