Gunmaker Sig Sauer has unveiled plans for a major expansion on a 20-acre parcel at the Pease International Tradeport. The proposed new development will include light manufacturing, warehouse space and office uses, the Portsmouth Herald reported. The project calls for creating a roughly 20.4-acre lot and a 182,500-square-foot facility on the site. The company is scheduled to present its plan for the proposed commercial development at the board’s Thursday morning meeting.