There are 3 actions here.

Copy item and raise one semitone.
Make sure you have the audio item you want to operate on selected, then run.
It will select the item, move to the end of the item, paste the copy and raise the copy by one semitone.

Copy item and raise one semitone 12 times.
Again, make sure your edit cursor is over the audio item.
then run this action and it simply calls the previous one twelve times.
You end up with 13 samples in a chromatic scale.

Convert item to samples in an octave.
Make sure your edit cursor is over the audio item on your track.
Run this action, enter a midi note to start your octave from  and you end up with your original sample now playing in an octave without the duration of the sample changing.  So no slow low notes or fast high notes.  They all play for the same time.
It depends on a script available in ReaPack:
MPL Convert selected items to RS5K items drum style
Search ReaPack for:
mpl_RS5k tools.lua
and also:
mpl_Various_functions.lua

The first custom action has the most entries in the action list, some of which are:
sws select item under cursor on selected tracks 
copy items depending on focus ignoring time selection
move cursor right to end of item 
paste items tracks
move cursor left one pixel 
sws select item under cursor on selected tracks 
pitch item up one semitone