The bushing will smash into the upper locking lug extension of a 5 inch barrel and damage both the bushing and the barrel and the the head of the recoil spring guide rod will smash against the forward angle of the lower locking lug and the gun will have difficulty in going into battery. Unless the lower locking lug is recontoured and the locking lug extension recut to match those of a Commander barrel, don't do it. Also, many 5 inch barrels have a reduced barrel diameter just aft of the muzzle, so you will need to obtain a 5 inch barrel that has a full diameter barrel from muzzle to locking lug.