Thanks lost sheep.
It is pure conjecture that the gun struck the MRI unit bore first, the article states "it is likely". Why? The gun presents a much bigger magnetic signature side-on, but this also is pure conjecture, as no-one knows. So a "slam-fire" is not a fait-accompli. In fact, if it was a slam-fire, why wasn't the MRI unit impacted instead of the wall at the rear of the MRI unit?
As to the composition of primers, I'll leave that to someone more knowledgeable than I, suffice to say I have seen "old" rounds with what appeared to be rust on the primer through some sort of plating. This is immaterial if you follow Lost Sheeps post.

quote:

Originally posted by Rockdoc:
Thanks lost sheep.
It is pure conjecture that the gun struck the MRI unit bore first, the article states "it is likely". Why? The gun presents a much bigger magnetic signature side-on, but this also is pure conjecture, as no-one knows. So a "slam-fire" is not a fait-accompli. In fact, if it was a slam-fire, why wasn't the MRI unit impacted instead of the wall at the rear of the MRI unit?
As to the composition of primers, I'll leave that to someone more knowledgeable than I, suffice to say I have seen "old" rounds with what appeared to be rust on the primer through some sort of plating. This is immaterial if you follow Lost Sheeps post.

Rockdoc,

You are most welcome.

I am compelled to point out that I disagree with your conclusion about the muzzle-first impact.

The "It is likely" phrase is, in my opinion, an understatement. The gouge in the paint of the bore of the MRI machine and the smear of paint on the recoil spring plunger at the muzzle of the Colt makes the muzzle first impact a virtual certainty. If it happened while the firing pin block was in the "up" position, a slam fire is a definite possibility. I am still waiting for a report of whether or not there was a firing pin indentation on the primer (which was not reported in the Journal's analysis).

On the subject of the magnetic signature or profile, orientation of the gun is irrelevant. The physics of magnetism tells us that.

A radar signature or profile does depend greatly on orientation, specifically, the silhouette presented and the angle of incidence of the surfaces facing the radar source and its absorptive properties. The force generated by magnetic flux on magnetic material is almost completely independent of orientation or shape.

Respectfully,

Larry (Lost Sheep)

I won't say it can't happen, but the only accidental discharges I have seen with the 1911 in all its forms was when the possessor carried it on half cock as opposed to cocked and locked..I carried one for 40 plus years cocked and locked, but don't recall ever dropping it, so couldn't say for sure...

Some new information:

I had an MRI on my brain this afternoon and took the opportunity to ask the techs what they thought of the possibility of various ways of producing a discharge. They tole me that in their training, they were told a bare cartridge could be made to go off because of the magnetic effects on the primer.

They were not totally clear if it was heat generation or movement of the anvil inside the primer, but it was definitely because of the high frequency of the magnetic flux (as well as its strength). Whether it was heat, electrical eddy currents or magnetically induced physical movement, is still an open question.

Anyone live near Rochester, NY who could contact Sgt Benwitz and ask if there was or was not a firing pin dent in the primer?

Lost Sheep.

Oh, the MRI on my brain. I won't have results for a while, but if they don't find anything there, I will be having a colonoscopy next month.

Thanks for the follow up. Did the MRI on your brain show anything? The implication here seems to be that the gun is irrelevant ie. the loaded (or even just primed) round is all that is necessary ie. the steel gun slamming against the MRI frame is irrelevant. all that is needed is to bring a loaded or primed round very close to the unit.
Peter

I am curious as to the firing pin mark as well. I firmly believe the magnetic force could "activate" the firing pin block (like a solenoid) Primer will tell the story for sure...