Modified my original design a bit for PETG printing. I use a lot less overflow and I added a bit of grip to the dart tubes. This allows for the use of new or old darts with a less consternation.
These models will probably work just fine for PLA as well, but I haven't tried it.
I'm using SCIGRIP 4 to weld these parts together. Do your solvent welding outside! This particular solvent contains dichloromethane, trichloroethylene and a methyl methacrylate monomer. If you don't know what those are, read up on them before using them.
Most parts are printed in Spiralize, so some test prints may be necessary ( don't worry, sources included in the Design section ).
With all flow restrictions removed, we hit 70 fps on the regular.
Steal the Hammershot peg from [Horsengineer] https://www.thingiverse.com/Horsengineer/about) from the 7-shot cylinder. That design is the inspiration for this build. So thanky-kindly. The primary difference is the liberal use of spiralize, so those tubes are smooth as butter.