Here's some chrono data;

Remington factory 125gr SJHP;

Dan Wesson/4" - 1456fps, ES 58fps, SD 18fps.

M686P/6" - 1627fps, ES 51fps, SD 22fps.

Sierra #5 ( latest edition) has full power 357 mag loading data.

From Lyman #47, factory equivalent 125s is 17.7grs/2400 powder;

M686P/4" CCI magnum primers;

5@1561fps - ES 32fps, SD 12fps.

Win mag primers;

5@1562fps - ES 38fps, SD 19fps.

AA #9/17.0grs - CCI mag primers;

5@1564fps - ES 54fps, SD 22fps.

The above loads are under max using Sierra #5 data, work up with caution and use proper loading protocol.

For those who are concerned about cylinder gap:

M629/6.5" 240gr Nosler JHP, N110/20.6grs/CCI 350;

6@1421fps - ES 34fps, SD 15fps.

Desert Eagle/6" 240gr Hornady XTP, N110/20.7grs/WLP;

6@1305fps - ES 23fps, SD 08fps.

N110/21.0grs;

6@1336fps - ES 15fps, SD 06fps.