Move a Sub-Directory Into Separate GIT Repository

I recently had a GIT repository with a sub-directory that should have been it own repository. I also wanted to keep all of the history in the sub-directory. These are the steps that I followed to move that sub-directory into a new separate GIT repository.

Old Structure

project/
  .git/
  p1/
  p2/
  p3/

New Structure

project/
  .git
  p1
  p3

p2/
  .git

Method

$ git clone --no-hardlinks project p2
Cloning into nuget-packages...
done.
$ cd p2
$ git gc
Counting objects: 640, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (225/225), done.
Writing objects: 100% (640/640), done.
Total 640 (delta 401), reused 605 (delta 390)
$ git status
# On branch master
nothing to commit (working directory clean)
$ git filter-branch --subdirectory-filter p2 HEAD -- --all
Rewrite 352c51285e647fc31d37aa42479162160def0594 (31/31)
Ref 'refs/heads/master' was rewritten
$ git reset --hard
HEAD is now at df4f12e removed nant from source control, it is now stored locally on the drive outside of the repository...
$ rm -rf .git/refs/original/
$ git reflog expire --expire=now --all
$ git gc --aggressive --prune=now
Counting objects: 671, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (646/646), done.
Writing objects: 100% (671/671), done.
Total 671 (delta 426), reused 214 (delta 0)