Among other things, there is disclosed a biopsy needle capable of taking samples of varying size. In particular embodiments, a user selects one of a plurality of sample-size settings, which sets the needle to a particular cannula throw-length by moving an internal wall against which a spring engages. For a shorter throw, the wall is in a forward position and the cannula is retracted the smaller amount to compress the spring. For a longer throw, the wall is in a rearward position and the cannula is retracted a larger amount to compress the spring.