I would look at the bed for the recoil lug any trash there can cause the problem you are describing.
You nailed it
Lee, that's where the problem is. The mortise for the recoil lug is way too large. Lots of play in there.
Probably just fine if you can move the barrel side to side in the stock... as long as it is not touching in one side or the other.
Sabotloader, the barrel was "almost" snug in the channel from the recoil lug rearward, and freefloated forward of the lug. What was happening is there's enough play in the recoil lug mortise that the barrel could shift with each shot and rest against one side or the other.