I have seen CI called several times when, *on the backswing* (ie, after the swing missed the ball and the bat barrel is going on around the BR's back) the bat hit the catcher's mitt. Since this is really *after* the BR swung and missed, is this really CI?

No it isn't interference.

<i> Originally posted by LMan

I have seen CI called several times when, *on the backswing* (ie, after the swing missed the ball and the bat barrel is going on around the BR's back) the bat hit the catcher's mitt. Since this is really *after* the BR swung and missed, is this really CI? </i>

If it's TRULY the BACKSWING - NO here's the applicable rule

<b> OBR 6.06
If a batter strikes at a ball and misses and swings so hard he carries the bat all the way around and, in the umpire's judgment, unintentionally hits the catcher or the ball in back of him on the backswing before the catcher has securely held the ball, it shall be called a strike only (not interference). The ball will be dead, however, and no runner shall advance on the play. </b>

Pete Booth

Discuss the same situation please with FED rules. The BRD
says the FED does not have what I've always been taught is
"weak interference", IE, the OBR rule of returning runners
to TOI and calling no one out. I'm thinking more of a play
I had this weekend where a catcher bobbled the pitch and
the batters backswing nearly hit the ball. If it had and the runners take off I'd be inclined to call "weak interference", return them and do nothing but Carl seems to
say in 262 in the 2004 BRD I should bang B1 out. I'm open
to advice and rule book support insight on this one. It
sure won't happen often but is damn interesting.

It would appear, that in FED, it is BI if the batter's backswing interferes with the catcher fielding a ball. After reading all the 266 commentary I think I would not bang the batter unless a runner is stealing (other than at 3B), or if the backswing prevents the catcher from holding a third strike.