Update. Second trip to the range with just the BCG wet still produced a single shot rifle. It would either not eject and jam or not strip off the next round. Following everyone's advice, I took one weight out of the buffer and replaced it with a piece of wood dowel rod. Worked almost flawless with my subsonic reloads. Still had one jam. I think it just needs more range time.
Reloads were 208 gn Hornady A-Max over 11 gns of IMR 4198. Here's the ballistic data for two 10 shot groups
Group 1 Group 3
Max 1148 fps 1147 fps
Min 1089 fps 1008 fps
S-D 31 39
ES 93 139
I didn't measure each load, just set the powder measure and loaded the rounds. I did check the weights a couple of times and make adjustments to make sure they were on target.
Here are the results, 50 yards with a red dot and 3X magnifier. Group on the left was bore sighted, and center group is after adjustment.