Kabigon

To check where the tank leaks at, pump it up and put it underwater. Where the air bubbles are coming from is where its leaking.

zhopp13@gmail.com

I use a variety of barrel materials to make hopper clips. You can use anything you fancy, or anything that you can nest inside of 1/2" Sch. 40 PVC. Generally you want a pretty tight fit for springer, and a looser fit for "airguns". (Some people don't know this, *cough* Brit *cough*) Let's start with some CPVC, a great barrel material for springers.

I don't quite understand this. Hopper clips rely on gravity to do all the work, right? So if you have CPVC or something that is tight, how is the dart supposed to fall into the barrel? Sorry if I misunderstood something here, but I don't get it.

As for the check valve... I was talking about having a check valve at both intake and discharge. The pump is effectively a 6-inch 2"PVC tube, capped at one end, with some 3/4" end caps drilled into and attached to that cap.
A small rod goes through each of the endcaps to approx. halfway between the endcap and the 3/4"PVC I'm using to connect the endcap to the pump. On the ends of these small rods, I have a rubber disk, similar to the SNAP plunger heads. Intake, the edge of the disc is inside the tank end, and discharge, the edge of the disc is inside the endcap. A length of vinyl tubing is attached to each one of the 3/4" endcaps.

Plans I've made call to place the pump inside the stock and the tank directly in line with the barrel.

If I understand what you're saying, you made a homemade check valve? My Home Depot sells pre-made PVC check valves. Maybe yours will sell them too. Buying one from there, if they have it, might be alot easier than making your own.

Anyways, I'm looking forward to see this get completed. It sounds very interesting.

Then for your other barrels just wrap e-tape until it fits.

Electrical tape will eventually wear down and leave this black gunky stuff on your coupler.

So if that happens then I will sand it off, and put some more. Its not a problem.

I sense a misunderstanding
I was arguing that your version of the universal coupler is more reliable then Kabigons version, which is to just slap on a coupler and then wrap etape around the pipe until it fits.

Yeah it may be more reliable, but I'm lazy . Whatever floats your boat!