~10 seconds iirc Irreg. can verify.

 

HAHAHA It's funny you mention that. I joke about that all the time because the standard is 4-5 seconds. I always found it ironic that as regimented as the Army is the couldn't come up with a firm time on something so serious as the time you throw and device capable of nearly vaporizing your body.

And for the record, hand grenades are a whole hell of a lot more powerful than what you see in the movies.

 

http://www.inetres.com/gp/military/i...enade/use.html

They're pretty damn fun. Here's a little info. on the common use M-67 frag grenade.