Had EXACTLY the same experience after I ran into two lightweight barrels that wouldn't shoot full floated. Up till then I full floated everything. Then I had a guy wanting to float a Model 7 in 7-08, and floated a M70 Featherweight in 300 Win Mag. Neither would shoot less than 3". First time that had ever occurred in 40 years. Bedded them neutral and they both went sub-MOA. Since then I've bedded the lightweights neutral and all have shot. There are no "rules".
