Bob's Home Made Bait Injector - 17.8881 in³ = 9.91202 fl oz(US)
I made three of these indentical, but alas I screwed up the nozzle on one (not in this picture). I cut the hex on the nozzle on the little MaxNC CNC mill I retrofit a while back. I also cut the end of the nozzle and the slope on it since I already had it centered on that machine. Then I did most of the rest on a mini lathe. I used a drill press to drill the nozzle, rod guide, and the back of the piston. Threading was done by hand with a thread cutting die. The hardest part (And how I screwed up the other nozzle) was putting in the stupid little locking pin. I have that figured out now though so it will be easier next time. Now to get back out in the shop and make a nozzle for that third injector.
Actual real volume is:
17.8881 in³ = 9.91202 fl oz(US)
However, I can easily cut a longer tube to make any size injector I need now. Just swap the guts.
I did discover I needed a lot less engagement on the piston O-ring than I originally thought, and I had to cut the O-ring groove deeper to reduce friction.
Before anybody picks on me:
1. I am not a real machinist.
2. My mini lathe is a prety crummy piece of equipment.