From the source:
When it came to purchasing a heavy artillery piece, the Israelis turned to their main armaments supplier, France, buying their Modèle 50 155mm howitzer. This weapon is quite heavy, but has an exceptional range, something the Israelis needed given the comparatively short range of most of their artillery park.
In order to increase its mobility, the Israelis paired the Modèle 50 with a modified Sherman chassis to create the first Israeli-built self-propelled artillery piece, the M50 / 155mm. This blend of excellent mobility and destructive firepower was put to good use by that the Israeli Defence Force during the Six-Day war.