Weirdly, the Tempest locked up again yesterday after my first shot with it in a couple of weeks. Just the same as before. I'd shot a couple of dozen pellets the week before that and no problem, but yesterday the problem recurred. I gave the sear a poke from below, just pressing with a pick and wiggling it around a bit, and it popped back into place and worked fine again to cock the pistol. I didn't shoot more as I had somewhere to go and haven't fired it since, but I'll give it a try soon and see if this keeps happening. This instance helps actually, as it makes clear that it's a problem with the sear's travel. Like it's over-travelling somehow, just a little, after firing. I might have to buy or make a new sear, once I figure out which part of it isn't quite right.