Grrr. Well, no luck so far. Just for giggles I swapped the receiver screw with the (longer) screw from my no.4. No dice. I fiddled with the lip on the mag. Nope. I took the extractor screw out of the bolt...but couldn't see an obvious way to remove the extractor itself. Eh? The spring feels pretty springy and the extractor does pull the shell out of the throat so....hmmm.