Sarg I attained 2190fps with 380s.
Bullet speed x bullet speed times weight divide by 450,420 2,190 x 2,190 x 380 / 450,420 = 4,046 fpe. And plenty for me.
E.g. 300 grainers. 2,500 x 2,500 x 300 / 450,42= 4,162 fpe.
A 500 grain 458 bullet at 1800 fps has 3,596 fpe.
And my humble call, given...