Current 6mm Grendel barrel makers: BHW, McGowen and who else?

[Sticks]

Velocity is a matter of pressure, all else being equal.

Insofar as number of grooves affects pressure, you'll see velocity differences. If number of grooves does not affect pressure, you will not see velocity differences. Typically, however, a barrel maker will make sure the area of the grooves — no matter how many — corresponds to the SAAMI spec for that cartridge.

If SAAMI spec says six grooves with an area of X, then a barrel maker will make four grooves slightly fatter so that they still have an area of X. Pressures will, thus, generally remain the same — and so will velocities.

So, do not assume that fewer grooves means more velocity.

Next, many barrel makers have told me that number of grooves, per se, does NOT affect accuracy.

How does this apply to the specs you gave Faxon on the GB Barrels? You explained it in another thread, and it makes sense. Are the GB Faxon barrels out of SAAMI Spec in the rifling?

Stonehenge & BFT - Would Faxon do a single custom cut?