Count max occurrences within rolling time frame

Hello!

I'm working with a very large data set (>1m rows) of time card punches. The goal is to find out the maximum number of punches that occur within a given time frame.

As an example, I want to find out the max number of punches within a ten minute time frame for the data below. The answer should come back as ten, for the time period between 13:25 and 13:34.

This set spans over 20 stores and 6 months (with punches anywhere between 6am and 11pm). Any ideas how to iterate this? I realize I could create SUMIFS up against two columns of times (6:00, 6:01) and (6:10, 6:11) etc., but was hoping for a better solution that would allow me to change the range of time from ten minutes to five minutes or whatever else my boss would like to see.

My data is simple, it's just two columns. I'm also posting a sheet (that has more and different info than below).

Store Time
29 3/23/14 12:57
29 3/23/14 13:25
29 3/23/14 13:25
29 3/23/14 13:25
29 3/23/14 13:25
29 3/23/14 13:26
29 3/23/14 13:26
29 3/23/14 13:26
29 3/23/14 13:26
29 3/23/14 13:30
29 3/23/14 13:30
29 3/23/14 13:37
29 3/23/14 13:37
29 3/23/14 13:37
29 3/23/14 13:37

I just wrote this, which is getting me there. Still not as iterative as I'd like.

=COUNTIFS($B$2:$B$300,"<"&B2+$E$1,$B$2:$B$300,">"&B2-$E$1)

With E1 being =10/(60*24) (to get the decimal amount that 10 minutes represents)

=(COUNTIF($B$2:$B$300,">="&E1)+COUNTIF($B$2:$B$300,"<="&E2))-ROWS(B2:B300)

E1 and E2 are Start and End times

In E1, you can simply enter 0:05 and it understands that is 5 minutes.
Since you are doing +/-, 0:05 represents 10 minutes, alternately, you could use 0:10 and in your formula, just use E1/2
I dragged it down and your statement that 10 would be maximum seems incorrect.

If you just want the maximum, you can enter this into a single cell (F1 for me) as an ARRAY formula
=MAX(COUNTIFS($B$2:$B$300,"<"&(B2:B300)+$E$1,$B$2:$B$300,">"&(B2:B300)-$E$1))
...confirmed by pressing CTRL+SHIFT+ENTER to activate the array, not just ENTER. You will know the array is active when you see curly braces { } appear around your formula. If you do not CTRL+SHIFT+ENTER you will get an error or a clearly incorrect answer. Press F2 on that cell and try again.