A high-pressure fluid injection system, which includes a rechargeable injection chamber with a proximal end, a distal end, and an internal opening extending from the proximal end to the distal end, a plunger slideably engaged with the internal opening of the injection chamber, an injection tube extending from the distal end of the injection chamber and in fluidic communication with the internal opening of the injection chamber, and a check valve between the proximal and distal ends of the injection chamber. The internal opening includes a high-pressure zone adjacent to the check valve and having a first diameter, and a low-pressure zone proximal to the high-pressure zone and having a second diameter that is larger than the first diameter.
