This is a brass barrel replacement for the Nerf firestrike blaster. The plunger I designed is assembled with a m3 screw and can be taken apart more easily. It will withstand moderate spring upgrades nicely, and show massive increases in performance. I don't have a chronograph to get fps for you, but maybe someone here will do it (cough, cough).
Notes:
There is a PDF install instruction manual in the files. It will explain what you need and how to do the installation of the parts.
The plunger padding should be made of something soft like ninjaflex at a low infill and isn't really necessary.