According to Buffalo Bore on their Heavy 357 Magnum Ammo - 180 gr. Hard Cast LFN-GC:
"This ammo is safe to shoot in ANY all steel 357 revolver - this includes J frames. This ammo is no harder on your gun than any other normal 357 ammo."
Can the LCR .357 handle it?
"This ammo is safe to shoot in ANY all steel 357 revolver - this includes J frames. This ammo is no harder on your gun than any other normal 357 ammo."
Can the LCR .357 handle it?