He places the bolt in the receiver so that it fits under the retaining rail as the <e1>bolt</e1> <e2>handle</e2> engages the groove in the bolt.
He places the bolt
He places the bolt in the receiver so that it fits under the retaining rail as the bolt handle engages the groove in the bolt.
<triplet> bolt <subject> handle <object> Component-Whole(e2,e1)