To much velocity and to light construction a bullet.
Your bullets blew up. Set up a target and try it out. Will happen every time. Now you know why the military uses FMJ ammo.

150 grain is on the light side for elk and moose anyways. Get some 180 grain Hornady SP flat base.
Speer Deep Curl or something tough. For big game flat base bullets fly straight on and don't yaw so much after impact. Also some brands like Speer make boat tail bullets with lighter jackets than there flat base bullets. Ballistic tipped bullets like Nosler, well they sell good don't they. I'm a big fan of Hornady Interlock bullets just old fashion soft noses. At 308 Win velocity it should be enough bullet. Now I suppose you'll tell us that's what you had and I''ll be here with my chin dragging.