An assembly for coupling a drug delivery device to a cartridge is disclosed. Optionally the assembly includes a coupling, for example a cannula, having one end extending toward the cartridge. The cartridge is optionally aligned by a guide. Optionally the cartridge has a limited freedom of movement. The coupling is optionally supported by a mount. In some embodiments, the mount is compliant enough that the end of the coupling that extends toward may move to said limited freedom of movement under a force less than a leak threshold of the connection between the coupler and the cartridge.