458 Express

Technical Information

Case design

Rimless, Belted, Boxer primed and straight wall.

The length of the brass cases in inches:

The .458 Express is not a 3.00'' (three inch case), it is indeed 3.00'' (two, nine, nine inches)!

View a technical drawing

The case capacity - measured using water and then weighed in grains:

**Velocities chronographed:

**Recoil calculations:

(It is taken for granted that the rifles weigh the same weight)

Chamber Pressure TESTS:

* Considerable less pressure is generated with the "duplex" loads, more will follow on that in the reloading section.

** For these tests we will use the same rifle and shoot loads over the same chronograph at the same temperature and atmospheric conditions.

*** Again it is important to use water, because no propellant will be filling all the corners of the case due to the structure and surface area of the propellant. The water provides for  a very accurate an ideal medium to conduct the test with.

*** All loaded with the same bullet, and not compressing a load. Compressed loads does not mean a thing in as test like this.

"tba" = to be announced. During all the tests I will be present personally and record data myself to ensure that we are uniform and consistent at all times.

Richard Jones a former Ballistic Technician with Sierra Bullets reminded me to mention that the .458 Winchester Magnum and the .458 Lott cartridges will indeed fire in a .458 Express weapon. Many examples of that scenario is happening in our area, especially when the professional hunters "forgets" to reload in time. It is not advisable because of the flash in the chamber but damage will not occur with a limited amount of shots fired. The performance of the shorter cased calibers will also remind you quickly that you indeed must utilize the superior performance of the .458 Express. Many thanks to Richard Jones for his input.

Designing a new caliber.

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