The Ark is at Kiriath-jearim

• Start — 1 Samuel 7:1. The year beginning the time the ark was in Kiriath-jearim (K-j) is the year David moved it to Jerusalem (2958) - the years it was in K-j (20) = 2938
• End — 1 Samuel 7:2. The year David's reign in Jerusalem began is the year he moved the ark there from Kiriath-jearim = 2958

START:[Ussher date p57] END:*HYPOTHESIS The year David began to reign in Jerusalem is the year he moved the ark there from Kiriath-jearim. [Ussher date p60]

Years are anno hominis — counted from Creation as year 1 — which is the frame the source computes in. The arithmetic behind each boundary is given above rather than assumed.