Hi All, The debate has raged about the 458 win mag for years and I just wanted to cut through the bull doo doo and try to compare some well loved calibres and the math behind their reputation. In the picture below, I have put down some facts and figures that are used to compare ballistics performance and then done some sums with those.Sorry it is all metric but I have put in the imperial units next door for most. Most columns are self explanatory but I have done a column of energy per mm2 of cross sectional area. My theory is that energy is what does the penetrating and X sectional area is a measure of the resistance to penetration ie the size of the hole / the energy available to make the hole. It just allows a comparison of different calibres. So here are my comments: 1/ 450 gr bullets from a 458 have the same sectional density as a 300 gr .375 bullet and have more energy per x sectional area than a 404 J. Maths suggests penetration would be in between those two ie less than 375 but more than 404 J. 2/ 458 win mag 500 gr at 1900 fps has significantly less energy per x sectional area than any of the others -30 to 40 %. This puts a number to the old stories from elephant culls etc. 30 -40 % less penetration would be a problem. 3/ Full power 458 win mag bullets are comfortably between 404 J and 375/416 in energy per x sectional area. That would suggest the penetration is between those. 4/ 375 and 416 rigby are highest in energy/xsectional area and in reputation for good penetration. Conclusion: This figure of energy per Xsecetional area seems to predict penetration quite well and follows all the well known opinions. So I think the 458 win mag with 450 gr is a real option for dangerous game and the 480 and 500 gr are even better. The numbers put it right in the middle of well respected calibres, between the 404 and 375/416. Let the games begin !