It is no mean feat to produce a "root cause analysis" based on a web picture.
As it turns out the OP and myself are the only ones here to look at the actual rifle involved.
Colt Canada examined the rifle of discussion with over 100 years of engineering experience, and real, professional engineers and technicians. Colt Canada, the Centre of Excellence for Small Arms for the Government of Canada, is responsible for small arms production, engineering and analysis including conducting investigations of exactly this kind.
The strangest thing by far about this thread is not that the damage is unique, but rather that a competing manufacturer would have the poor judgment to use the opportunity to undermine another manufacturer in a public forum.
Of all the gun damage Kevin claims to have seen and has based his analysis on, I would be curious exactly how many involved a breech overpressure incident in an improved hammer forged carbine chamber with steel cased ammunition? Colt Canada was able to re-create the incident in a lab with consistent damage using steel cased ammo.
I assume no pictures or high speed proof is available?
It seems that the Knight’s Armament’s “laboratory” re-creation of the exact same type of incident would have been lacking a few of the fundamental components, like the specific kind of rifle, the specific kind of ammunition, and any first hand knowledge of any part of the incident.
So KAC has no access to the same ammunition, rifles, or testing facility? I guess they wouldn't have first hand knowledge of this incident, since it was a Colt.
Kevin’s description of a "dangerous overpressure round" sounds an awful lot like an incident with a conventional brass case. Colt Canada has seen and created a great many of these types of breach overpressures in many different ways. They have been recorded with high-speed cameras, subject to numerous modern methods of examination and the components cataloged for future reference and use in training organizations to conduct formal firearms investigations. Noting that the key element in this particular incident was notably different than a conventional breach overpressure we discounted those findings and compared the damage with breach overpressures with that type of case. I’m sure Knight’s Armament’s root cause examiner noticed that too.
I assume they are classified, no way you can post any of those pictures or videos here of the same failure?
Kevin did say "generally". Of course, this is a pretty “specific” incident that the OP experienced involving a steel case and a not a brass case. Would you be prepared to testify in court as to how a steel case should fail when improperly charged with this exact firearm? Colt Canada would, and we have a generous amount of experience, qualification and evidence to support our findings.
Again, can you show a direct comparison of the two? I mean an over pressure round in both brass and steel case in the exact same two rifles?
The user described an overpressure incident with a rather loud bang and had a very difficult time removing the bulged case. Readers might have also noted that he decided to continue firing until the component failed. Many readers seemed not to have noticed that Colt Canada readily agreed to formally examine the item, and did so very quickly, and then decided to repair the rifle despite the fact that it had been modified by the user and that there was an ammunition incident.
Kevin might have also noted where Colt Canada pointed out in this thread that the material had been examined and eliminated the possibility that “there was a pre-existing fissure/defect in the upper forging that was not detected earlier”. Of course if you have any evidence to the contrary, I would love to see it.
