jonno, welcome to the forum.

Have you tried the Sierra 140 gr. JHP? If so what do you think of that bullet? Corbon loads a .357 JHP load with it and it sounds like a good one, although I haven't tried it (I'd rather handload than pay for overpriced ammo). My experience has been that Sierra JHPs behave much like Remington SJHPs, exibiting serious secondary fragmentation, good penetration, and slightly smaller recovered diameters than non-fragmenting bullets.