The goal of this modification is to create a CPVC-couplered NiteFinder (NF) that is also efficient (as far as “dead space” is concerned), clean-looking, and durable. It's actually loosely based on this brass, non-couplered NF modification by Dart Attack.
Seeing as this is an NF modification, you will of course need an NF.
Unscrew and remove the battery cover at the bottom of the grip, then unscrew the 14 other screws. Carefully remove the right half of the shell, and you should see this:
You will also need a CPVC coupler and some ½ inch CPVC for a barrel. Optionally, you also want some thinwall ½ inch PVC. For the newbs in the audience, here is a picture of the proper CPVC and coupler next to ½ inch PVC and a ½ inch PVC coupler.
Immediately remove the catch spring, as it tends to want to shoot off into the dark corners of the room once you start moving the internals around.
Unscrew the two screws holding down the plunger tube, and disassemble the plunger tube assembly. The only parts you need to save are parts A, B, C, and D.
Take piece A and cut out the middle.
Smooth out the inside of piece A so that you can fit your CPVC coupler inside.
Now take piece B, snap off the peg, and dremel out a hole in the middle of it that’s just big enough for a piece of CPVC to easily fit through it. Here’s what it will look like when you’re done:
Put pieces A and B together as they were when stock, then slide in the coupler as far as it will go.
Now cut off the extraneous portion of the coupler, like so:
Once you’ve done this, take those three pieces apart and epoxy them together. Be sure to wipe off any epoxy that gets inside the coupler.
Note: for simplicity, let’s refer to the conglomeration of the coupler, piece A, and piece B, as the “coupler assembly.”
If you so desire, you can also epoxy the coupler assembly onto the main plunger tube (labeled piece C, above). I didn’t do that.
While you wait for the epoxy to dry, take your plunger (piece D) apart by removing the screw in the center of the plunger head. Remove the stock spring and replace it with a stronger spring, or add a spring to it. I did the latter, using an AR-15 buffer spring cut down to the size of the NF’s spring. Thanks go to Bogboogalars for the idea to use an AR-15 spring.
Also, you’ll want to replace the stock o-ring. I used two that I got from Busy Beaver. The fit is perfect; I believe it was #116, with an outer diameter of 15/16 inch.
Don’t forget to use some silicone-based (and not petroleum-based) lubricant.
Once the coupler assembly has dried, you can reassemble the plunger tube.
Since I didn’t epoxy the coupler assembly to the main plunger tube, I wrapped the joint in electrical tape.
If you don’t want to epoxy the coupler assembly onto the main plunger tube, you’ll need to make a “buffer” to keep the coupler assembly from being pushed off by the plunger. The buffer is a piece of thinwall ½ inch PVC. The thinwall PVC has a large enough inner diameter that CPVC can easily fit through it. You’ll need to make it fit in front of the plunger tube; mine looks like this, except I smoothed it a little after I took this picture:
Since you’ve added a spring, you’ll need to put in a more powerful catch spring. Actually, I find that adding the spring from the N-Strike rail to the stock catch spring works well.
Put everything inside and close up the NF.
Finished internal and external pics:
Note that I put some electrical tape around the buffer and minimized the NF. Mostly just because I wanted to.
And, with a speedloader:
I haven’t tested exact ranges, and I don’t expect them to be much different from my other CPVC-couplered NFs; however, this one looks much cleaner than the others, in which I simply epoxied a coupler onto the end of the plunger tube. Plus, it's impossible for the coupler to break off.
There were some concerns when I posted this on NerfHQ:
jwasko, do you have problems sticking the CPVC too far into the coupler (the ring that blocks the CPVC halfway through isn't there anymore)?
Also, my CPVC couplers aren't perfectly cylindrical, they get "fatter" toward the middle, so its kinda wierd.
Lowes' couplers have always been tapered like that, for me. Just recently, Home Dept has gotten ones that are similarly tapered; however, the change in outer diameters is not as severe as the Lowes ones that I have seen. The coupler that I used was an old (untapered) Home Depot one; the new ones should work with some dremeling, but I haven't tried it.
While it is true that the ring is gone, the cut was made just before the ring; therefore, the coupler is quite tight by the time it gets to the back. Unless I really put some force on it (say, use a hammer), I am not getting the CPVC through there; and I wouldn't push it in that hard, since at that point it would be quite difficult to remove and flip the barrel.
Now, if your CPVC has an unusually small inner diameter (or the coupler an unusually large inner diameter) you should worry about that. I, personally, did not have this problem.
If you feel the need to, however, you could modify the modification:
1. Cut the coupler where you need to so that the ring still exists.
2. Stick it in piece A-B backwards (with the ring pointing towards where the back of the blaster would be)
3. Cut off extraneous coupler
4. Dremel out the new end of the coupler
5. Put the coupler in the right way and epoxy
Step 4 is the reason why I preferred to simply cut off the ring; the ends of the coupler, when "stock," are slightly beveled. This makes it easier to get a barrel into the coupler. If you cut off this beveled portion, it's harder to put the barrel in and so you have to recreate the bevel. I have tried recreating the bevel in the past, and it has never worked quite as well as the stock one.
As a third alternative, I suppose you could leave the coupler a little long. But, that would cut down on the plunger volume.
As a fourth alternative, just position the two speedloader barrels so that the barrel that is not being used keeps the other from going into the coupler too far.
I've found when I use either a PVC cutter (like this http://www.chinatrad...0524537532.jpg) or a pipe cutter (like so http://ots-inc.org/i...ipe_cutter.jpg) it usually creates a little ring at the bottom that acts as the lips use to