This project is getting underway and I've ordered the parts. This design shares many components with the PCSR I built. The difference is that the foregrip and pusher rod from the PCSR is replaced with a moving plunger tube face which has a ramrod in the end of it. And that ramrod has a mag-well just ahead of it. The barrel is nested inside of the tube that the foregrip slides over.
A fair amount of inspiration from the revshot, though I started with a completely empty sheet of paper.
The only hiccup I've run into is that this is going to have a clear plunger tube that's floating. It is held in place without screws as the structure is all external to it.
The old part number (8585K43) that used to be for ordering that size of tubing in 1-foot lengths has been replaced and McMaster no longer sell it in lengths shorter than 8 feet.
So if you want to make a Rev.2 Plusbow or anything else with an identical plunger tube you should order this part from Amazon instead. It's available in 3-foot lengths for $11.54 w/ free shipping if you have a Prime account.
https://www.amazon.com/Polycarbonate-Tubing-Wall-Clear-Color/dp/B00193SSMO
Or you may want to switch to using aluminum instead. The part number for an aluminum plunger tube in identical dimensions is 1658T18 (for 2 feet).