Blocked Punt Recovery Rule

[V_wenzel]

Team A has the ball 4th-and-Ten from Team B's 40.  Team A elects to punt.  The punt is blocked by Team B behind the Line of Scrimmage (never crossed LoS) and is recovered by Team B at the 50.  Team B elects to run with the ball (after gaining full possession) and fumbles the ball at Team A's 45 and is subsequently recovered by Team A.  Who's ball?  Does Team A still have to make it back to the original Line of Gain?

[maven]

A's ball, 1/10. Once B recovers the kick, whoever ends the down in possession will have a new series.

This rule is the same at every level. The NFL reference is 7-3-1c.

[V_wenzel]

Thanks Maven.  We've been going around and around with this one!