Home Forums Hunting & Shooting Express Rifles and Big Bores Only The great 458 Winchester. Everyone should own one at least once

The data bertzs supplied was assumed to be from 5-yard chronograph and corrected to MV.
Close enough for Crusade work.
To compare his 22 " barrel to my 24" barrel results, I also added 40 fps to his H4198 velocities for the Monoflex.
Again, close enough for Crusade work.
If the COL he used was shorter than 3.340" he might gain a little pressure and a few fps velocity advantage for same powder charge versus the longer COL,
but only a very little, due to the SAAMI .458 WM throat efficiencies, or is that just magic ?
Accuracy might be a little better with a longer COL, maybe not, since the SAAMI .458 WM throat is a great accurizer with all COLs possible.
I got out my pencil and graph paper again:



Enlarged for hopefully easier reading for old eyes:



Very close agreement.
Another big buy a donkey to beretzs for saving me some components.

Maybe the diminishing returns above 80 grains of H4198 are due to heavy compression of that powder ?
Even there I bet pressures are less than those of the .458 Lott MAP.

The 250-gr MonoFlex is a short range bullet due to rapid velocity loss and wind drift, i.e. low BC.
Speeding it up from 2725 fps to 3075 fps gains only about 50 to 60 yards of practicality.
It is very pleasant in a .458 WinMag at lower velocity and loses velocity less rapidly.
Using a 90% LR net fill with AA-5744 for 2725 fps MV makes a lot of sense to me, especially in Daisy, since she likes that load best.