I have had three of them. Two were the M70 Super Grades of about 1971 vintage. 22" barrels. In Australia they were priced just under a Mark V Deluxe in 300 Wby at the time. A 375 M70 was midway between the 458 and the M70 XTR in 270. Later I had a Ruger #1
My favourite loads were the 400 grain Speer with 70 grains of 4064 which did right on 2000 f/s (with the original Ohler 10 ad paper screens) and 70 grains of 3031 that was right on 2100 f/s. All three rifle were ragged hole stuff at 100 yards. Similar results with other people's 458s as well. Never shot anything big if you go to hell for shooting kangaroos, pigs, goats and emus with a 458, i will be there for a long time. It absolutely flattened stuff.
Recoil about like the 375 when loaded with 4064 and 2400 with 300 grains and 2600 plus with 270 grains, 68 grains and 71 grains. Muzzle blast much less, sort of flat bang.
I know that a of blokes have used full loads with mono metal bullets of 350 grains. I never did anything with the 350 Hornady as had a 460 at the same time and that is 3000 f/s stuff.
Of course if you had a 458 with the 3.6" length full length magazine you load it to equal the 458 Lott.
It just might be the most versatile over 30 calibre out there. A lot of fun for sure. Of course with cast bullets it adds another dimension. Maybe in these times of shortages you could make your own black powder and cast bullets. I thing the 458 would be similar to the 45/100 or 45/90??
