Got the new OEM upper, tried it with the factory lower (minus the mag safety) and factory bolt. 60 rounds of this Federal 36 grain plated bulk, 4 soft rounds that wouldn't cycle the slide, 2 hangfires. Tried the same ammo with original upper, 10 rounds, 3 soft rounds including a stovepipe, one hangfire. Tried same ammo in Browning Challenger, 60 rounds, no soft rounds, no hangfires, one dud/misfire which fired on restrike.
Onward and upward, I guess? Going to try to find a parts kit to complete my new OEM Ruger upper and see how it works. Worst case I'll have another .22 pistol after all this.