
10" of 1/2" PVC
1 1/2" of 1/2" brass
1 foot of PETG (I'm using OMC Thick-walled)
e-tape
Plumber's Goop
Small ring of CPVC
Dremel with cutting wheels and sanding bits, or other cutting/sanding devices
A air duster is also helpful to clear off all of the PVC dust.
Take your PVC and round out one end (this is the one that will be going into the coupler)

Now make a mark 1" from that end, and then another 3" after that.

Now mark out a dart slot.

Cut it out.

Now take your 1 1/2" of 1/2" brass and wrap e-tape around one end until it makes a good seal when slid into the PETG. Make it snug so it won't blow off when shot, but not so tight it is hard to remove.

Then wrap e-tape around the other end so it fits snugly in the PVC.

Glue it in with either Goop or superglue.
Now take the PETG and wrap tape (I chose masking tape) around it in several places so it doesn't jiggle around in the PVC too much.

Slide the barrel back in and mark the place where it meets the back part of the dart slot.

Take your CPVC and cut about half off.

Goop it on at the mark.

Now you're done! Let the Goop dry, and you should have a nice PETG breech.

If I ever get darts that fit in PETG well for air guns and springers, I would completely switch to these. As it is my darts fit weird, so I'll still be sticking to my Brass breech's for springers, and PETG ones for air guns (one of each for my crossbow (at2k integrated)).
I'll also be selling these if anyone would like to buy them. $11 shipped for one or $8 each with $3 for however many you buy. If you're intersted please post in my Sales thread (sig) or in my Breech sales thread. Let me know what you guys think of the prices also.
Questions? Comments?
-OfAll'