My 52 likes just a teeny bit more power than what I normally use in revolver WC loads to reliably cycle.
Grayfox's comment mirrors my experience and I neglected to mention it a few months ago, in my initial post. Some people also think slower powders work better in 52s, thus 231 or something similar might be a good bet if Bullseye is not doing the trick. The comment about trimming brass to minimum makes perfect sense, but I admit I have not checked mine.
HKSmith, as your LNIB gun is used, it should wear itself in to a condition that suits it, and start to work better, so temperature may have nothing to do with it. The gun warms up pretty quickly when you start shooting it. I would think how clean it is and how you lube it would be more important. Having said that, I have shot more than a couple thousand rounds through my 52-2, trying to be systematic about cleaning and lubing it, and it still hiccups - even with handloaded ammunition that has been checked in a gage. Makes one think we are dealing with a very tightly chambered gun, thus the suggestion to trim the cases back to minimum is probably a very good one.
Speaking of wearing-in your 52-2, Gil Hebard once published a pretty extensive test of 52s, IIRC shooting them huge numbers of rounds and observing them carefully for accuracy. It seems the 52s did indeed not function up to their capability until they had shot-in, and then they went many, many thousands of rounds without substantial loss of accuracy. The number at which he found accuracy started to fall off escapes me now, but it seems it may have been around 75,000 rounds - maybe even more. I believe he tested four guns and got similar results across the board. At that time, the pistols appeared to be very consistent, from gun to gun.
