A drug delivery device includes a casing and a storage container with a dose delivery member, at least a portion of which extends through an opening in the casing. A guard is movable relative to the casing between extended and retracted positions. The guard surrounds the extended portion of the dose delivery member in the extended position, and exposes the extended portion in the retracted position. An interference arrangement is included for providing selected threshold of resistance to movement of the guard from the extended position to the retracted position during insertion of the dose delivery member into body tissue. The arrangement has first and second members engaging one another to retain the guard in the extended position. The first or second member can move if the selected threshold of resistance is exceeded to allow the members to slide and allow the guard to move into the retracted position.