Same diameter bullet, but the benefit of the Max round is being able to load heavy-for-caliber bullets, up to 250+ grains in handloaded ammo.
Is it a revolver or a single shot (T/C barreled Contender)? If I remember this right, there was an issue with gas cutting of the forcing cone with revolvers. This occurred at a fairly low round count too. Maybe some of the more gun smith type members will be able to add a little more insight.