What the guy found.
The Lonoke County Sheriff's Office says a man called them saying he just recently bought a car from a local scrap yard. While cleaning out the car he found an item in the wheel well in the trunk inside a plastic cup.The man says he took the item and placed it under a trash can in his yard. When the Sheriff's Office inspected the item, they say it looks like some type of a grenade with an extremely rusted pin which was still intact.The Sheriff's Office called the Arkansas State Police bomb squad who took the grenade. The bomb squad says it doesn't appear to be a live grenade. The grenade was turned over to the ATF.
Well, based on my limited experience this looks like a M49A1 Trip Flare, without the mounting bracket:
The M49A1 Trip Flare is an early warning signaling device used to warn of infiltrating troops by illuminating the area surrounding the trip flare.The M49A1 Trip Flare consists of an illuminant assembly, cover loading assembly and a mounting bracket assembly. The illuminant assembly is an aluminum case containing an ignition increment and three illuminant increments. The waterproof cover loading assembly contains a percussion primer, intermediate charge and a spring-loaded striker.The Flare is armed by attaching a Trip-Wire to either the trigger or pull-pin. Once the Trip-Wire has been breached, either the trigger tongue or pull pin will release the lever, which in turn permits the firing pin to strike the primer. The primer sets off the intermediate charge, and the intermediate charge ignites the First-Fire composition on the ignition increment of the Flare. The M49A1 Trip Flare will provide a light intensity exceeding 35,000 candle power for approximately one minute.
Unlike hand grenades, the ignition is instantaneous without a delay and they burn hot as hell. I mention them in the Absolved chapter Black and Tans and also discuss them in the praxis post on military pyrotechnics. In order to use them to break contact at night, you have to carry them without the bracket and pull the pin and throw them behind you in one fluid motion while running away -- unless you want your hand burned off. Personally, I would be made more nervous by finding a rusty one of these than I would a live frag.