Here is Kilk Custom Fountain Pen with plunger mechanism.
It has double reservoir. With single shot it sucks 1.7ml of ink. With a technique shown in the video linked below, it can get up to 2.7ml of ink..
Second reservoir holds 0.6ml of ink.. German ebonite and AA resin combination. 24k goldd plated brass clip and rings. Plunger rod is also gold plated. Nib unit is JoWo#6 gold plated steel.
Here is the link of the video showing filling demonstration: https://youtu.be/2dE5PAagEhU