357 Magnum – Remington UMC – 125 Gr. JSP Ammo Test andreleger2001 1 year ago 357 Magnum – Remington UMC – 125 Gr. JSP Ammo Test Jug Test, Chronograph Results, and Water Expansion Test of the 125 Gr. UMC JSP Ammo by Remington in .357 Magnum.