unknown firing pin

[RNLMC]

gentleman.
A couple of weeks ago i came across this firing pin(?). Now, several sleepless nights and countless visits to google later i still don`t know
wat weapon or piece of ordnance this firing pin is from. Is there any body out there who can help me?

with kind regards.
werner.

 

[Darrol]

Hi.The only firingpins ive seen with a groove /hole going through them was on selective fire mortars . . Bit the point of the pin looks to fragile .Dont know if this is any help. :/Darrol.

 

[Charlie]

Any dimentions?

 

[RNLMC]

dimentions: length overall: 4.229 inch/107.4mm. width at the tip: 0.094inch/2.42mm. width at the end: 0.389inch/9.8mm.
At the end (on top) there is the marking GM. which made me think general motors.(or one of the sub-divisions). however
nothing came up. I can`t think of any bomb-fuse a firing pin this size would fit in but i`m no expert. still any idea is
welcom.

werner.

 

[Jimiles]

Werner, it's got to be 30 years since I last saw one but I'm pretty certain that's a firing pin from the .50" M8C Spotting Rifle.
Jim