A surgical instrument , comprising: (a) a body ; (b) an ultrasonic blade extending distally from the body, wherein the ultrasonic blade is operable to apply ultrasonic energy to tissue; (c) a clamp arm assembly comprising a clamp arm pivotably coupled with the body at a pivot assembly , wherein the clamp arm is operable to compress tissue against the ultrasonic blade, wherein the clamp arm assembly further comprises a clamp arm base , wherein the clamp arm base is configured to be secured to a distal end of the body, wherein the clamp arm is pivotably coupled to the clamp arm base, wherein the clamp arm is operable to pivot toward the ultrasonic blade to thereby compress tissue against the ultrasonic blade while the clamp arm base is stationary relative to the body; wherein the instrument further comprises: (d) a detent assembly, wherein the detent assembly is configured to provide tactile resistance to pivotal movement of the clamp arm relative to the body beyond a predefined pivot angle, wherein the detent assembly is configured to permit pivotal movement of the clamp arm relative to the body beyond a predefined pivot angle upon application of a force sufficient to overcome the tactile resistance, characterized in that the detent assembly comprises: (i) a clamp arm detent feature on the clamp arm, and (ii) a body detent feature on the clamp arm base, wherein the body detent feature is configured to complement the clamp arm detent feature, wherein the clamp arm detent feature and the body detent feature are configured to selectively restrict pivotal movement of the clamp arm relative to the body when the clamp arm base is secured to the body. (a) a body ; (b) an ultrasonic blade extending distally from the body, wherein the ultrasonic blade is operable to apply ultrasonic energy to tissue; (c) a clamp arm assembly comprising a clamp arm pivotably coupled with the body at a pivot assembly , wherein the clamp arm is operable to compress tissue against the ultrasonic blade, wherein the clamp arm assembly further comprises a clamp arm base , wherein the clamp arm base is configured to be secured to a distal end of the body, wherein the clamp arm is pivotably coupled to the clamp arm base, wherein the clamp arm is operable to pivot toward the ultrasonic blade to thereby compress tissue against the ultrasonic blade while the clamp arm base is stationary relative to the body; wherein the instrument further comprises: (d) a detent assembly, wherein the detent assembly is configured to provide tactile resistance to pivotal movement of the clamp arm relative to the body beyond a predefined pivot angle, wherein the detent assembly is configured to permit pivotal movement of the clamp arm relative to the body beyond a predefined pivot angle upon application of a force sufficient to overcome the tactile resistance, characterized in that the detent assembly comprises: (i) a clamp arm detent feature on the clamp arm, and (ii) a body detent feature on the clamp arm base, wherein the body detent feature is configured to complement the clamp arm detent feature, wherein the clamp arm detent feature and the body detent feature are configured to selectively restrict pivotal movement of the clamp arm relative to the body when the clamp arm base is secured to the body. (i) a clamp arm detent feature on the clamp arm, and (ii) a body detent feature on the clamp arm base, wherein the body detent feature is configured to complement the clamp arm detent feature, wherein the clamp arm detent feature and the body detent feature are configured to selectively restrict pivotal movement of the clamp arm relative to the body when the clamp arm base is secured to the body. <EOS>