While the Federation answer for this one is pretty trivial, the NCAA answer will require some thought:

<b>PLAY:</b> 4th down, A12 punts from his 10. Ball is blocked and rolls into the end zone. A12 recovers in the EZ but then fumbles. Ball rolls out to the 2 and comes to rest. A diving Team B player muffs the ball (not a bat) and ball is knocked back into the EZ where A44 recovers and advances for an apparent 1st down.

NCAA. Ruling: A's ball 1st and 10 at the 20. Reason: The impetus for the ball being in the end zone is from the muff by team B of the "at rest" ball. The recovery by A44 causes the ball to become dead due to the 4th down fumble rule. By rule the ball will come back to the spot of the fumble which is in the end zone in which the impetus was provided by team B.

NF, 1st down for K.

Jason, in NCAA if A12 had recovered his own fumble in the EZ and ran beyond the LTG we would have a down, correct?

I'm an NCAA guy, so I'm curious - why (and where) is this K's ball in Fed?

I'm not a Fed guy but I'm 99.9% that Fed doesn't have a 4th down fumble rule, so the advance for the first down is legal.

I think the NF rule that applies here is 6-2-3. "Any kicker may catch or recover a scrimmage kick while it is in or behind the neutral zone and advance, unless it is during a try."
K can always advance a scrimmage kick anytime it is behind the neutral zone. In this case they advanced it for a 1st down.

It was no longer a scrimmage kick. The moment K12 recovers the blocked kick it became a run. The question is, does Fed have a 4th down fumble rule that requires the player who fumbles to be the only K player to advance the ball? I say there is no such rule under Fed, but that's just a guess.

No fourth down fumble rule under Fed.

Canadian Ruling
 

A would have to have reached the line to gain to earn a first down.

The impetus that put the ball in the end zone for A12's fumble was the blocked kick, not B's muff. After B muffed the ball back into the end zone, there was no second fumble. If, under the 4th down fumble rule, the ball cannot be advanced and comes back to the spot of the fumble, the result would be a safety.

Blocking of a kick does not change impetus. Check out NCAA rule 8-7-2. Impetus is charged to the player who kicks, passes, snaps, or fumbles, or contacts a ball at rest.

Exactly. Team B was NOT responsible for putting the ball in the end zone prior to A12's fumble.

Safety.

Exactly. Team B was NOT responsible for putting the ball in the end zone prior to A12's fumble.

Safety. [/B][/QUOTE]

Team B's muff of the "at rest" fumble is what put the ball back into the endzone. Therefore Touchback for Team A 1st-10 at the 20.