A few questions for guys who have had their HBR's fluted:
1) what are the ideal dimensions (width, depth) for fluting a 1 inch stainless bull barrel?
2) is it possible to flute the entire length incl. the gas block section or will that create installation problems?

Thanks in advance for yoiur replies.

You do not want to flute the gas housing portion. You can flute either side of of the housing, but most do not go beyond nera the rear of the front sight housing. Micro fluting is best for cooling since it provides more cooling surfaces, plus great strength. I like 1/8" depth/width on 1" barrels, (expensive). However if a tappered barrel, best way to go, the fluting depth needs to get more shallow as the barrel tappers to the front.
Good Shootin, Jack

Thanks for the reply. Good point about the gas housing although that leads to another query, if you don't mind; My plan was to install a mid-length FF handguard on a 20" bull barrel. I assume that the barrel would have had the gas hole drilled to fit a long handguard - is that the case? Would that mean that the mid-length handguard would not work then?

You can have the barrel maker put the gas hole anywhere you want him to. The mid length gas hole is 2" further out than the carbine.
Good Shootin, Jack