I like the Jetstreams, but had a few black refills that I had acquired over a few years in 0.5 and 0.7 prematurely stop flowing. The black cartridges in the new

I like the Jetstreams, but had a few black refills that I had acquired over a few years in 0.5 and 0.7 prematurely stop flowing. The black cartridges in the newest Jetstream pens I've purchased have been fine. Not sure if they had a few bad batches that took a while to clear out of the market, but it was disappointing.