Mate, I nearly had the same problem when I first went to buy some co2 bulbs for mine. In the instructions with the keg charger it stipulates to buy non-threaded co2 bulbs, even though the charger has a female thread where the bulb is inserted. I was asking at several homebrew shops for non threaded, and none could supply. Luckily I guess.I bought a "genuine innovations" keg charger from brewers discount a few monthes back which came with an unthreaded bulb. I then bought 16g unthreaded bulbs from finewhip.com.au ($20 for 10) which look the same but when trying to fit the charger, are actually slightly wider at the tip and (unlike bigfella mentioned in an earlier post) are slightly longer than the charger chamber.
I just thought i would bump this thread because I purchased these under the description of "beer chargers" and yet they dont fit a beer charger and one would need calipers the actually measure the size difference that makes them useless.
Has anyone tried cutting out the thread in the charger (like bigfella) except to fit bulbs slightly longer? Might fit?
Or are the threaded cartriges all the same so I would be better off keeping the thread in the charger and buying threaded new cartriges?