Lets not forget where the H barrel originated from, a cut back lee metford (to measurements) barrel. yes it was thought to be better harmonics and that it still was approved by the NRA at the heavier than standard weight barrel because it was dimensionally the same as the lee metford one. I haven't ever had a lee metford apart to examine the bedding set up but would be betting it wouldn't be much different than the SMLE. So what Iam trying to get around to saying is that it doesn't have to be fully floated to shoot better. In fact i have seen some old range No1 mk3's with that much cork on top of and below it that it would'nt move if it had a truck trying to bend it!!and they shot very very well.
Cheers
Ned