OK, nobody is going to die, so I will show you guys one way of doing the UBR on a PTW so that you don't have to pop the buffer cap and you have access to the battery in mere seconds.
Now, here is the gun, and the stock fully collapses:
Now, a closer view of the stock:
Now, here is how I chose to fix the stock on the buffer tube. It is a brass knurled nut ($1.29 at Home Depot) that I drilled out and tapped for M6 x 1 for a clone UBR (you didn't think I was going to try it first shot on a real one, did you?). A real one is Imperial threads, and that is easier to find parts for. I cut an M6 x 1 screw to allow me to access the buffer tube with threads to screw the stock on. The nut is going to get painted black, but I left it brass to see easier in the pics:
Now, in order to accomodate the nut and still be able to fully collapes the stock, I needed to drill a hole through the butt. This is nicely hidden by the rubber butt pad:
It takes mere seconds to unscrew the nut, and then you simply slide the stock off. This was a clone, and the fit and finish is not like the real deal (but it is 1/5 the price), so I needed to sand the buffer tube some to get the stock to slide nice and smooth.
Once the stock is off, you have access to the battery and the electronics. I cut a notch with a Dremel into the buffer tube to be able to slide a battery in place. You see the stock EL-003, and realize right away that you need a shortened board, the stock one is about 1" too long. Mine is still on order, but I proceeded with the mods pending its arrival.
Also, to get to this point, you need to deal with the takedown pin spring and detent. Normally, these are floating and are held in place with the stock. However, this stock comes off, so that would not do. I opted to tap a small set screw in place, cut a little bit off the spring and screwd it and the detent in place. Now, there are no issues, and it does interfere with any stock installation, be it UBR or not.