I forgot that the ammo I took the most of(some Winchester Super-X) doesn't have quite enough oomph to reliably cycle the conversions. Happily, did find a box of Remington Thunderbolt in the bag, and both cycled just fine with that. I'll have to dig out more of the hotter stuff for this.
The 15-22, on the other hand, ate everything. One reason I chose it is that it's only the second .22 semi-auto rifle I've used that would reliably cycle with subsonic ammo, so figured if the CherryBalmz wouldn't quite cut it, it would show up here. So far, so good, put twenty Remington subsonic and twenty Eley Sport through it with no problems other than a couple of the Remingtons needing a second strike to fire. Same with the Winchester a few times in rifle and pistols both.
So, initial result: no functioning problems other than ammo-related. More shooting to go.