Yesterday I shot some factory loads through the chrono.

458 wm
A Square 465 gr rn & monolithic. Published at 2220, actual 2215.
Hornady 500 gr rn & solid. Published at 2200, actual 2100.
Winchester 510 gr rn. Published at 2040, actual 1990.

338wm
A Square 250 gr rn & monolithic. Published at 2220, actual 2210.
Winchester 230 gr fail safe. Published at 2780, actual 2812.
Winchester 200 gr power point. Published at 2960, actual 2892.

338 shot through HS Precision bolt 26". 458 through Beretta double 24"' Five shot strings.

For what it is worth the A Square is my choice. The softs and solids hit to the same point in both calibers. The 338 Fail safe went through a 1/2" steel plate like armour piercing--a perfect round hole. Maybe not a good choice for game. It reminded me of Barnes triple Shock---too much penetration. I hope this is helpful.