270 WSM loads

[ForneyRider]

I starting to work on these loads now.

Mostly looking at R19 and R22 loads...

Norma has 61.7 of 204 for 3288fps as MAX. 204 is between R19 and R22 in speed(brisance???).
Alliant has 66gr of R22 at 3228fps, and 66gr R19 for 3088fps MAX. Win brass and CCI 200 primer
Nosler says 65gr of R22 in WLRM primed Win brass for max load but highest fps.
Lyman has 68gr of R22 for max load.

Lee book doesn't cover very many powders, except Hodgdon and Winchester.

It was a G&A or Shooting Times article comparing 270 Win and 270 WSM and they used 130gr Scirrocco's with 68gr R22 for max load.

I think all this data was collected using Win brass, except for Norma.

What are ya'll using?

 

[Unclenick]

Don't have a WSM, but can tell you burning rate and brissance are not the same thing. Burning rate of a powder is tested in a caloric bomb that simply measures how fast a standard shaped quantity of the powder takes to burn up? Brissance is a measure of the violence of a detonated explosion. The test is actually done by detonating the explosive in sand, then measuring how much shattered sand was produced? If the gas is created rapidly enough, a strong shock wave results that shatters a lot of the sand grains. If the gas is made a little more gradually, the shock wave is broader with a lower peak pressure and shatters less sand. Primer mixes are evaluated as to their brissance. Progressive powders burn so slowly that no meaningful shattering of sand can be produced by it unless it is detonated. So brissance has no meaning as a measure of progressive burning performance, AFAIK?