what bullet for a .41 mag
If what he was shooting was the Federal Cast Core bullets, it should be loaded with a Cast Performance bullet. Those bullets are not supposed to really expand. Hard Cast bullets are more for penetration rather than expansion. A lot of people here seem to prefer the jacketed hollowpoints for deer sized game rather than the hard cast ones. Hornady makes a 210 grain XTP that would probably work pretty well. I don't personally use a 41 but the XTP has a good reputation. Sierra makes a 210 JHC and Speer makes a 200. I would probably try the XTP first.
If what he was shooting was the Federal Cast Core bullets, it should be loaded with a Cast Performance bullet. Those bullets are not supposed to really expand. Hard Cast bullets are more for penetration rather than expansion. A lot of people here seem to prefer the jacketed hollowpoints for deer sized game rather than the hard cast ones. Hornady makes a 210 grain XTP that would probably work pretty well. I don't personally use a 41 but the XTP has a good reputation. Sierra makes a 210 JHC and Speer makes a 200. I would probably try the XTP first.