Spontaneous Discharge of a Firearm in an MR Imaging Environment

American Journal of Roentgenology ^ | 6 November, 2001 | Anton Oscar Beitia1, Steven P. Meyers, Emanuel Kanal and William Bartell

[marktwain]

An incident recently occurred at an outpatient imaging center in western New York State, in which a firearm spontaneously discharged in a 1.5-T MR imaging environment with active shielding. To our knowledge, this is the first documented case of such an occurrence.

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An off-duty police officer went to an outpatient imaging center (not affiliated with our institution) in western New York State to have an MR imaging examination. The facility housed a 1.5-T MR unit (Signa; General Electric Medical Systems, Milwaukee, WI) with active shielding. The officer was carrying a model 1991 A-1 compact.45 caliber semiautomatic pistol (Colt's Manufacturing, Hartford, CT).

The officer notified the technologist that he was carrying the weapon before entering the MR dressing room. The technologist told the officer to take the gun with him. The technologist intended to meet the officer in the MR patient waiting area before the examination and secure the weapon in that room, where he felt it would be safe. However, the officer apparently misunderstood and took the gun into the MR suite. The technologist was entering the officer's personal data into the computer and did not see him entering the MR suite.

Once the officer was inside the MR suite, the gun was pulled from his hand as he attempted to place the gun on top of a cabinet 3 ft (0.9 m) away from the magnet bore. The gun was immediately pulled into the bore, where it struck the left side and spontaneously discharged a round into the wall of the room at the rear of the magnet. Fortunately, no one was injured.

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The weapon's thumb safety was reportedly engaged when the gun discharged.

[laotzu]

I carry a Glock...

Ya know...if he had a Macintosh he wouldn't have this problem.

[CrazyIvan]

A 1911 should not fire unless the thumb safety is off and the grip safety depressed prior to squeezing the trigger. Unless the MRI unit released these safeties, or the gun was in an unsafe condition; either worn parts or kept unlocked with the hammer down on a chambered round, or a combination of both, I don’t see how this could happen.

I think that inertia could move the firing pin forward with enough force if the gun impacted muzzle first. Anyone else want to weigh in on this? I know I’m going to check out my
1911 when I get home and see if this is possible. (No, I’m not going to throw it against the wall to find out!)

[AnAmericanMother]

I also smell a rat.

There's a grip safety AND a thumb safety. The grip safety, IIRC, is plastic or aluminum. I don't see how the MRI could simultaneously release the grip AND the thumb safety, AND cause the firing pin to move forward. All these moving parts are in different places and move in different directions . . . .

My guess is that either he had the hammer down on a round (very unsafe and unnecessary) and the hammer struck the primer when the pistol hit the wall of the MRI, or he just had an AD while fumbling with his pistol and is blaming it on the MRI.

I don't have my 1911A1 on me, so I don't remember if it has a hammer block like my Sig or my little Walther. But I think having the hammer down would bypass it even if it did have one.

[Dumpster Baby]

[Shooter 2.5]

enjoy your big fat mostly plastic tinker toy.

I'm sure he does. Beware the man who only has one gun. He probably knows how to use it.

[Vaquero]

i was talking about PowderMonkey Glock from post 6.

[P8riot]

Yeah, I read the complete story AFTER I posted (a bad habit). It seems the magnetic field disengaged the firing pin block and allowed the firing pin to strike the primer discharging the weapon.

[murrie]

This is not the fault of the officer. I have worked
in MRI environments-it is the technicians/nurses responsibility to deal with “prepping” the patient. Then
again, it could be that the tech was intimidated by the
big, bad gun that they weren’t sure what to do.

I don’t care how many safeties, ect are on a gun. When you have a gun vs an mri the mri will win everytime. Guns were not designed to withstand an mri environment.

[csvset]

I've had several MRI's as well. The place I went to ensures that you aren't bringing any metal anywhere near the MRI room. You're wearing nothing but your scivies & a hospital gown . Anything you wore or brought in with you is locked in a dressing room well out of the vicinity of the MRI room.

I had had a piece of rust removed from my eye 15 years prior, they insisted on checking my eye with some sort of scope before allowing me to proceed w/ the MRI.

[Jonah Hex]

OK, admittedly one of the few incidents where a handgun got up on its own and tried to shoot somebody. ;-)

[P8riot]

1911s don’t have hammer blocks. Some, like this one, have firing pin blocks that don’t allow the pin to travel unless they are moved out of the way by the action of the grip safety (none of mine do and I have over two dozen 1911s). After reading the story it appears that the magnetic field actuated the firing pin block and allowed the firing pin to set off the round, either through the action of the magnetic field or the impact of the weapon against the tube.

[AnAmericanMother]

Now what are the percentages on that shot, do you suppose?

What do folks with stainless steel pins in their hands (like me) do? My knee injury predated MRIs.

I've heard you can get a CAT scan on 75% power.

[AnAmericanMother]

I guess steel bridgework and pins or screws in your bones are a no-go, then?

[Pistolshot]

I call it a BS story.

ALL Colt 1991 1911's have the Series 80 firing pin safety pictured in red below.

The firearm cannot fire unless the trigger is pulled, the grip safety engaged to ALLOW the trigger to move, and the manual safety off.

Colt went through a HUGE liability case and this 'modification' to the design was the result.

[SES1066]

Sounds like the officer is not smart enough to carry a weapon.

I respectfully disagree.

The officer notified the technologist that he was carrying the weapon before entering the MR dressing room. The technologist told the officer to take the gun with him.

Unless you have experience with high-gauss fields / equipment, you are unlikely to appreciate their reach and power. The Officer informed the proper person who 'assumed' the Officer understood what was not clearly communicated. Fortunately only property damage and a good object lesson about assumptions!

[CrazyIvan]

Is that a Solidworks drawing?

[mikey_hates_everything]

Regardless of the firearm mechanics, safety on or off, an internal spark, caused by eddy currents generated by flying metal through that strong of a magnetic field and igniting the gunpowder within the round would cause me concern. Nothing explosive, especially surrounded by any type of conductor, should be near an MRI.

[Vinnie]

I’ve got a stent and a titanium/ceramic aortic valve. Both supposed to be non-magnetic.

Not sure if that prevents my having an MRI or not.

I’ve worked in the vicinity of machines but never closer than approx 15’-20’.

[Sender]

Magnets are awe-inspiring things. I have some neodymium magnets only an inch long that are so powerful they will cause injury if your skin happens to come between them. I had some six inches in diameter which would distort a TV or computer monitor from 10 feet away. They would also erase videotapes, floppies or credit cards in the room. I finally gave them away as being too dangerous.

I can only imagine 1.5 teragauss.

[kAcknor]

Inertia will indeed cause discharges in a fall.

The original design of the 1911 has a pin susceptible to it, but some designs today do not. The force needed to actually do that will vary based on the weight of the pin and the forces of any (if present) springs it has to overcome to do so.