Despite other matters(exhaustion), I needed to run out anyway so I loaded up some stuff and hit the range. Due to circumstances(forgot a part) I didn't try the conversion today. What I did try was the S&W 15-22 and the K38.
The 15-22 has very little to lube: the two rails the bolt rides on and the recoil spring guide rod; wiped them down thoroughly and gave them a light dose; moving the bolt by hand, it felt very slick and smooth. The K38 I disassembled, cleaned the parts thoroughly- including a flush with brake cleaner- and put on a light coat before reassembly. Dry-firing it the action felt just as slick as it had with the Lubriplate grease.
I put 100 rounds through the 15-22. I did have four problems, all the same thing: the bolt hit the next round in the mag in such a way that it tipped up instead of sliding forward. Could just be happenstance; it's not an unknown FTF. Only way I can think of to blame this on the lube would be if the bolt was moving faster than before and the round couldn't feed up properly. I doubt it. More testing will come. After I got home I pulled the bolt assembly; no dirtier than with anything else I've tried, and the bolt still moves very smoothly.
Added: ref the above, I'll make it clear: this is a problem that's occurred before and I do not blame it on the lube; it's pretty clearly an ammo problem. I think something is out of spec on some cartridges and it causes this. I threw in the 'only way I can think of' due to brainstorming, which doesn't mean that the storm wasn't more of a light shower of little consequence.
The K38 is hard to tell, it's such a smooth action to start with. I can say this stuff appears to be just as slick as any other lube I've tried in a revolver. One advantage of oil over grease: you can put just a small drop in place and it'll flow between two parts, whereas with grease you have to put the stuff on before assembly to make sure both surfaces are coated.
I need to polish a piece of steel and oil it with this stuff and then leave it sitting out, see how the stuff does on corrosion resistance. And in the next range trip I promise not to forget the damn part, so I can try the conversion with it.