Here's Sir Gerald's opinion Jose, from the second edition of
The Modern Shotgun, 1948, The Diagnosis of a Burst
In order to give the investigator every possible chance of arriving at the truth the gun should be sent up for examination as soon as possible, and without being cleaned. Accompanying the gun should be the fired case of the cartridge which actually cause the burst; if possible the fired case of the round immediately preceding the burst, a few fired cases, and as many unfired cartridges as possibleof the batch which was being used at the time.
With this evidence available it should be possible to diagnose the cause of the accident with certainty. By far the most common cause of burst is some obstruction in the bore, and so the first thing to do is to look for evidence of an obstructional (
sic) burst, that is for a ring bulge.
If a ring bulge is detected the cause of the burst becomes established beyond any shadow of doubt.He also observed that lifting of the rib was typically found with a ring bulge.
