Update: I called several machine and tool shops about Dykem Blue. None of them had any clue what I was talking about.
Asked my dealer about it. She knows what it is, but doesn't have it.
Another regular was there, and asked what I wanted to do. I told him about the problems I'm having. He suggested a black marking pen, or candle soot. Said he's done both in a pinch.
Got home and did the candle thing. The locking area on the barrel (both upper and lower lugs) and the slide rails sooted up nicely. Reassembled, racked the slide a few times... and no joy. No rub marks. Still binding.
Time to give up?
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"The evils of tyranny are rarely seen but by him who resists it."
-- John Hay, 1872