Remove the bolt then slide the cocking support and handle back and forth in the channel to see if it is catching. You are seeing if the channel is pinched down.
Also check that the cocking support lever pin is properly seated in the support and the end is not hanging up the cocking support.
Examine inside of cocking tube for evidence of burn through from welding in the cocking tube sleeve and sEA'sam to reciever.
Examine the cocking tube where it enters the triple tree to see if it is close to center, should have a gap on all sides and not be touching the triple tree.