@bacardisteve I believe these cases go back to the seventies or even the sixties.
They go back even further. The same trigger mechanism was used on the Remington M721.
One Greybeard I know told me of two hardware store new M721's that discharged through the floorboard of cars when their safeties were taken off. The owners were unloading their rifles while standing beside the vehicles.
I found this thread:
http://thefiringline.com/forums/showthread.php?t=307130
Did you notice in the first thread where the guy's M721 discharged when the safety was taken off.
This thread lead me to the Remington factory recall
http://www.firearmsid.com/Recalls/FA_Recalls 4.htm
REMINGTON
MODEL 700,CENTER FIRE RIFLES MFG BEFORE 1982
MODEL 600, 660, 721, 722 40-X RIFLES MFG BEFORE MARCH 1982
MODEL XP-100 TARGET PISTOL MFG BEFORE FEBRUARY 1975
RECALL: Remington Arms Company, Inc. is offering a safety modification program for certain bolt-action centerfire firearms manufactured prior to 1982, including the Model 700, Model 600, 660, 721, 722, 40-X bolt-action rifles (made before March 1982) and Model XP-100 target pistols made before February 1975.
These firearms have a feature known as a bolt-lock that requires the safety to be placed in the “off” position in order to unload the gun. If you participated in this program, your firearm will be modified to eliminate the bolt-lock feature. The operation of your gun will not be otherwise affected.
http://hunting.about.com/od/guns/a/aacbsnewsrem700_2.htm
I have read a number of threads on the M700 trigger. One thread, a poster reported a death that occurred in El Paso when an owner was unloading his M700 in the drive way of his house. It discharged in the air, but a lady, perhaps mowing the lawn, was killed when the bullet hit her.
The Remington over ride trigger and its sear blocking safety have reinforced in me a distrust of over ride triggers in general, and sear blocking safeties in particular. I believe a proper rifle safety holds the firing pin back, like a M98 or M70. The only mechanisms with military two stage triggers are military rifles, those triggers are just about impossible to jar "off", but the market likes over ride triggers and their tiny sear engagement surfaces. So that is what we have.