The picture posted by Daniel shows an interesting variant on a gentleman's sporting shaft, if you compare this to the Lutrell Psalter picture (used on the cover of Hardy's "Longbow" and also shown in "The Great Warbow") you will see a different nock aperture, not the triangular shape of this Burgundian example on a clearly bobtailed shaft, but more of an enlarged "C" shaped nock aperture shown in use for shooting at the butts in an earlier period, also with the interesting bulbous head with the marks made by these heads on impact with the clay face of the butt.
Neither of these are primarily bulbous nocks so as to be "pinch gripped" as we usually understand the term, they are far more likely to be "clip on" in function, something not in evidence on a livery shaft for warfare, partly no doubt for reasons of economy of production, partly for the reasons given by Ascham in making his distinction in nocking depth and function between shafts for war and shafts for sport.
It should also be borne in mind that primary and secondary pinch grips, where employed, set a lower draw weight limit on the bow than that which would be used in a heavy war bow culture for fighting, though it should be noted that Gaston Phoebus does make a recommendation that a lighter draw weight than that typical in a war bow might be usefuly be employed for hunting.
Not that I expect that this is addressed to the common archers, but obviously to literate gentlemen who may well have been less frequent users of the bow.
It is also worth noting that with a basic pinch grip, above a certain draw weight, the arrow escapes the grip, like it or not.
Where a primitive culture uses a very heavy bow, we do not see a simple pinch grip in use.
For example, the Liangulu elephant hunters, drawing around 100 lb use a grip not unlike a Mediterranean loose.
FWIW
Rod.
