RBP Rev2 Plunger rod.
I've moved away from using the traditional 1/2" Nylon and cutting out a notch. The reason for this is when moving to the Rev2, the slots in the back were eliminated. I figured the string stop would align the plunger rod enough to work, but every once and a while, the plunger rod would magically rotate out of place causing the blaster to not catch anymore. So I figured it was time to design a multi-directional catch notch. Kane actually gave me the idea initially, and I went with it. First I tried using 3/8" rod, with 3/8" x 1/2" tubing over that. This initially worked fine, worked all of Apoc, and then I started noticing problems with it not catching. I'm not surprised in the first place because 1/16" isn't much room to catch, even for the Rainbow catches. In the final version, I used 1/4" aluminum rod, with 1/4" x 1/2" polycarbonate tubing nested over. At the end of the polycarb tube is where it actually catches. I did a drop test while primed and it still stayed caught after dropping it from waist level on concrete (even though part of the pump tube broke(small problem being addressed)).
In this design, the plunger head is "floating". The rod doesn't go through the length of the plunger head to allow for the air to vent through through the plunger head when priming, thus eliminating vacuum loading, the number one problem with misfeeds in hoppers. In later iterations, I plan on extending the tube near the front, and pouring silicone RTV in the void for my flap valve. This will be easier to do and will result in a perfect seal everytime.
The last important thing to mention is I think I'm moving away from the string stop. Instead, I'm going to add a couple (or few) of these rubber grommets between the end of the pump tube, and the piece of Sch. 80 it pushes on to prime. I will do a bit more testing on this to make sure I'm not ruining other parts of my blaster when dry firing it.
This post has been edited by Ryan201821: 02 September 2011 - 11:40 AM