While MkVIIIz is a popular topic...

[Parashooter]

. . . I read this as saying that the use of MkVIIIz caused accelerated wear due to the difference in the shape of the projectile base causing a concentrated heat area up the boat tail out to the barrel, rather than the base of the FB projectile meeting the barrel at a tangent . . .

This seems not in agreement with the statement in the last paragraph of section 4 in the displayed document:

"* Although the use of Mark VII and kindred types of cordite loaded, flat base bulleted, ammunition reduces Mark VIIIz barrel life, the reverse is not the case." (emphasis added).

What actually may to be implied is that the accelerated erosion from cordite Mk VII ammunition can render barrels too worn to perform well with the shorter bearing surface inherent with boattail bullets of the same weight, a result easily attributable to greater opportunity for yaw in the worn throat.


Simplified sketch showing how boattails have a greater propensity for yaw in worn throats than flat base bullets.

Numerous tests over the years have demonstrated the popular idea that boattail projectiles hasten barrel wear is based more on imagination than fact. The article below summarizes some of the test results.