[Rubygems-developers] Can't pull down gemspec

[Trans]

Well, I've tried everything I can think of, but I can't seem to find a
way to pull down the gemspec of a specific version of a gem. All I can
get is the most recent version.

  $ gem spec --remote turn

But

  $ gem spec --remote turn -v0.5.1
  ERROR:  Unknown gem 'turn'

Any ideas?