The critical shoulder angle
was measured as the angle between the line joining the superior and inferior glenoidal margins and the line connecting the inferior glenoidal margin to the lateral-most aspect of the acromion (Fig.
During reach and retrieval with gravity compensation, all subjects showed less elbow extension and, in eight subjects, a decrease in shoulder angle
and/or plane of elevation.
These indicate that men tended to have slightly less shoulder angle
abduction and elbow flexion than did women for these reaches, especially toward the latter phase of the reach motions.
Its 25-degree shoulder angle
is steeper than most of its contemporaries, contributing to the ageless appearance.
Ackley reduced the original cartridge's body taper and changed the shoulder angle
to 40 degrees, which allowed for greater case capacity.
Taking the basic SOCOM case, Wilson pushed the shoulder forward 0.030" while maintaining the same shoulder angle
. The results were twofold.
has a longer case, a shoulder that is slightly farther forward and a shallow, 2 5-degree shoulder angle
that puts the neck/shoulder junction much farther from the case head than the .30 Nosier.
Remington changed the shoulder angle
from 15 to 20 degrees.
The case length is 2.035 inches, and the shoulder angle
is 30 degrees.
They shared the same features intended to enhance feeding, chambering, and extraction such as a tapered body and moderate shoulder angle
. Incidentally, the more recently adopted .338 Lapua Magnum also shares those attributes.
Wildcatting cartridges from existing cases offers innumerable options in shoulder angle
, neck length and body taper, so there were numerous versions.
The 6.5x55 has a slightly thicker, larger diameter rim, and its shoulder angle
is a bit steeper, but the 7x57's case is a bit longer.