A system for delivering an injection of a fluid into a void within a subject is disclosed. A barrel extends from a first end to a second end and forms a lumen extending from the first end to the second end. A plug and a floating seal are arranged within the lumen. A hollow needle includes a distal end with an opening for fluid to flow from the lumen. The plug, the barrel and the floating seal include material and dimensions selected based on a threshold flowrate for a fluid arranged within the lumen to: overcome a force opposed to a force being applied to the fluid in the lumen to move the floating seal and the hollow needle into a tissue of the subject, and succumb to the opposing force to displace the fluid through the opening into the void.