Looks like my usual sources are dried up as well. Not surprising, it is a discontinued design.
However there are a few workarounds.
This hose from an old version of a Raptor will work on the body...
...however it won't work with the stock bottom line on an Afterburner. The linked hose does use 1/8npt threads, which is the standard hose threading for aftermarket bottom line accessories, so you can use it with a different bottom line. Most aftermarket bottom lines have a single line of holes, so you'd mount it to half of the holes on the bottom of the Afterburner's grip, offset a bit to one side or the other.
Since you have the left hand threaded version (I thought Afterburners were newer than that and had the later right hand threads? oh well, learn something new every day), you can replace the hose with a vertical ASA (air source adapter).
Then you can run a small tank vertically, or add a regulator, expansion chamber, or gas through grip. Those will have to be combined with an aftermarket bottom line (stock one has proprietary threads), and a new standard hose.
There are a few more options for the mechanically inclined. How handy are you with a drill and set of thread taps?