Sir Bevan, CEB makes a 400-grain Lever Solid that differs in having a shorter nose projection so it will fit in lever actions. Otherwise it is constructed like the 450-gr and heavier solids. This "Special" 400-gr brass FN was made with the bands moved baseward for a greater nose projection, and also differs in having a greater interband Minor Diameter that is larger, 0.449", only 0.001" less than bore dimeter so it is closer to riding the bore. Michael McCourry designed it for use in his .458 B&M which has less nose room and shorter throat, as well as helping me out by getting something better for loading in the .458 WinMag with 3 bands ahead of case mouth, crimped right up against the bottom of the third band. Trimming brass to 2.490" and seating even closer up against that third band, you can make it 3.340" COL instead of my 3.360". Or seat it with only 2 bands ahead of case mouth and make the COL 3.250".
CEB would have to be asked to make another run of these, they are not a regular catalog item. If I were doing it specifically for the .458 WinMag I would want an even greater nose projection. Move the bands even more baseward, so as to crimp between the 2nd and 3rd bands and get a COL of 3.340". Then I could still crimp behind the third band and get a LongCOL .458 WM+ load also, heh-heh-heh.
The Lee Factory Crimp Die for the .458 WinMag is a standard, regular production item. Used to be about $15. In the Biden economy they are probably a lot more now. Made for many standard calibers. If I see one that I don't have I buy it, whether on dusty shelf or on internet sales catalog.
This batch of Norma .458 WM brass gives no indication of softness. One fire-forming ought to make it hard. I will anneal case mouths after third firing.
Benchmark seems to be as good as AA-2230/AA-2460 and supposed to be more temperature stable, though AA-2230 /AA-2460 ain't bad in any way. Try both and see what you like best.
Ron aka "Rip" for Riflecrank Internationale Permanente NRA Life Benefactor and Beneficiary .458 Winchester Magnum, Magnanimous in Victory THE WALKING DEAD does so remind me of Democrap voters. Donkeypox.
