No conclusion can be drawn based on the information provided, the protruding primer indicates the case locked onto the chamber but did not stretch the case between the case body and case head, meaning it would appear that case had a reduced load, or the barrel is worn out, a worn out barrel will allow the bullet to run down the barrel without forcing a build up of pressure, or, the bullet diameter was too small.
The hole in the primer is about the .7854 thing, the pressure inside the primer was greater than the firing pin spring could/can hold, meaning the pressure inside the primer/case forced the firing pin back when the dent in the primer was removed or by design, the pressure inside the primer cause the primer to conform to the nose of the firing pin.
The fact the primer backed out indicates the rifle has excessive head space, the amount of head space can not be determined by protrusion on a fired case because there is a lot of movement between the case and primer, I am guessing, you had cases that were ejected without protruding primers? On those cases and assuming the case locked onto the chamber, the cases without protruding primers stretched between the case head and case body, I do not shoot 303 British rear locking rifles, I do not shoot Krag 30/40 rifles, again, I check head space first, the effort is not worth the failure built into the design, have a 1905 Ross and P14s that have or soon to have Wildcat type chambers.
F. Guffey
