A surgical instrument, comprising: a handle comprising: a first handle member, a second handle member including a second handle member proximal end portion pivotably attached to a proximal end portion of the first handle member; and an actuation mechanism configured to provide a releasable connection between the handle and a tool body (240, 260), the actuation mechanism comprising an elongate linkage member disposed longitudinally within the first handle member, where the linkage member includes an elongate body with a distal-end ball-engagement cage, an intermediate dual-camming region, and a proximal-end pivotable attachment structure that is attached to the second handle member, where a first side of the intermediate dual-camming region slidably contacts a first camming surface within the first handle member, said first side including a generally longitudinal first contact portion and a second generally longitudinal contact portion offset from the first contact portion, where the first side of the intermediate dual-camming region is dimensioned such that generally longitudinal movement of the linkage member along and relative to the first camming surface occurs along a first line when the first contact portion contacts the first camming surface and occurs along a second line, non-collinear with the first line, when the second contact portion contacts the first camming surface. a handle comprising: a first handle member, a second handle member including a second handle member proximal end portion pivotably attached to a proximal end portion of the first handle member; and a first handle member, a second handle member including a second handle member proximal end portion pivotably attached to a proximal end portion of the first handle member; and an actuation mechanism configured to provide a releasable connection between the handle and a tool body (240, 260), the actuation mechanism comprising an elongate linkage member disposed longitudinally within the first handle member, where the linkage member includes an elongate body with a distal-end ball-engagement cage, an intermediate dual-camming region, and a proximal-end pivotable attachment structure that is attached to the second handle member, where a first side of the intermediate dual-camming region slidably contacts a first camming surface within the first handle member, said first side including a generally longitudinal first contact portion and a second generally longitudinal contact portion offset from the first contact portion, where the first side of the intermediate dual-camming region is dimensioned such that generally longitudinal movement of the linkage member along and relative to the first camming surface occurs along a first line when the first contact portion contacts the first camming surface and occurs along a second line, non-collinear with the first line, when the second contact portion contacts the first camming surface. where the linkage member includes an elongate body with a distal-end ball-engagement cage, an intermediate dual-camming region, and a proximal-end pivotable attachment structure that is attached to the second handle member, where a first side of the intermediate dual-camming region slidably contacts a first camming surface within the first handle member, said first side including a generally longitudinal first contact portion and a second generally longitudinal contact portion offset from the first contact portion, where the first side of the intermediate dual-camming region is dimensioned such that generally longitudinal movement of the linkage member along and relative to the first camming surface occurs along a first line when the first contact portion contacts the first camming surface and occurs along a second line, non-collinear with the first line, when the second contact portion contacts the first camming surface.